Syrian government forces killed at least 100 people on Tuesday in assaults on villages and an artillery barrage in the restive city of Homs, activists said, while the Red Cross called for daily ceasefires to allow urgently needed aid into the war-torn country. Two Western journalists, one American and one French, were also reported killed. Indepdent observers estimate that since the uprising in Syria began last year, about 7,500 people have been killed.

Washington, which is preparing for a “Friends of Syria” meeting of Western and Arab states opposing President Bashar al-Assad, declined to rule out eventually providing arms to rebels seeking to overthrow him.

U.N. chief Ban Ki-moon said he was searching for a candidate to name as a humanitarian coordinator for Syria, whose role could evolve into seeking a political solution to the conflict.

Ten children and three women were among the dead, the opposition activists’ organization, which documents what it describes as killings and human rights abuses by security forces, said in a statement. The two journalists were killed in the besieged Syrian city of Homs on Wednesday when shells hit the house they were staying in, opposition activists and witnesses said.

They were named as Marie Colvin, an American working for Britain’s Sunday Times newspaper, and French photographer Remi Ochlik.

A witness told Reuters by phone that shells hit the house where the journalists were staying and a rocket hit them as they were escaping. Both were veteran reporters of wars in the Middle East and elsewhere.

In Damascus, security forces opened fire on demonstrators overnight, wounding at least four, activists said. Violence has hit the capital over the past week, undermining Assad’s assertion that the 11-month-old uprising against his rule is limited to the provinces and the work of saboteurs.

Activist accounts of the violence could not be confirmed. The government bars most foreign journalists from Syria.

The International Committee of the Red Cross said it had asked authorities and rebels to agree daily cease-fires so life-saving aid can reach civilians in hard-hit areas including Homs.

“It should last at least two hours every day, so that ICRC staff and Syrian Arab Red Crescent volunteers have enough time to deliver aid and evacuate the wounded and the sick,” ICRC President Jakob Kellenberger said.

Western and Arab powers that are openly seeking Assad’s downfall are preparing for the inaugural meeting of a “Friends of Syria” contact group in Tunisia on Friday.

Asked about the prospect of arming the rebels, U.S. State Department spokeswoman Victoria Nuland said: “We don’t believe that it makes sense to contribute now to the further militarization of Syria.” But she added: “That said...if we can’t get Assad to yield to the pressure that we are all bringing to bear, we may have to consider additional measures.”

Russia and China back Assad’s own program for reforms, which includes plans for a referendum on Sunday on a new constitution which would lead to elections in 90 days. Assad says this should satisfy demands for more democracy; his opponents say the proposals are a sham.

Russia said it would not attend the “Friends of Syria” meeting because the Syrian government would not be represented. Lebanon, which has tried to distance itself from the turmoil across its border, will also stay away from the Tunis meeting.

Russia and China have faced Western and Arab criticism for blocking U.N. action against Syria. A former Syrian Defense Ministry auditor who defected in January told Reuters that Moscow’s arms sales to Damascus - nearly $1 billion last year - had increased sharply since the start of the uprising.

In an interview with Reuters, U.N. chief Ban said he was urgently contacting prospective candidates for the role of U.N. humanitarian coordinator for Syria. The U.N. General Assembly asked Ban last week to name someone for the job. Russia has said it would support a U.N. humanitarian envoy.

Meanwhile, activists said government forces launched the artillery attack on Homs after rebel fighters holding the opposition Baba Amro district blocked troops from entering.

“Several shells are falling each minute,” activist Nader al-Husseini told Reuters from the district.

The British-based opposition Syrian Observatory for Human Rights said security forces had stormed villages in Idlib province in the north of the country.

Activists in Homs said government forces backed by armor have been closing in on Baba Amro, a mainly Sunni Muslim neighborhood, since the offensive on the city began on Feb 3.

Much of the opposition to Assad comes from the Sunni majority, while much of his support comes from minorities including his Alawite sect, raising worries that violence could take on a sectarian slant and draw in neighboring countries.

Tanks are deployed in the Inshaat district next to Baba Amro, opposition sources said. The Observatory said a convoy of more than 50 armored vehicles was seen heading from Damascus toward Homs.

A city of 1 million people on the Damascus-Aleppo highway, Homs has been at the heart of the uprising against Assad’s 11-year rule. Residents say they are running short of medicine and food, and are massed together in crowded homes to seek shelter. Government curbs on access make it hard to verify details of fighting there but international rights and aid organizations say hundreds of people have been killed in recent weeks in Homs.

Assad, however, says the revolt is the work of foreign-backed terrorists. Until recently it was limited mainly to the provinces, but anti-government rallies have drawn crowds in Damascus in recent days. On Monday night at least four people were wounded when security forces opened fire, activists said.

Elsewhere, an activist group in Kfar Tkharim near the Turkish border said rebel fighters had killed five soldiers and captured two in an ambush on a government column.

An activist in al-Qusair, about 32 km (20 miles) southwest of Homs and close to the Lebanese border, said five people were killed and eight wounded when the northern part of the town came under heavy fire from army mortars and T-72 tanks.

“People in that area are hiding in their homes, they can’t leave. Others are resisting. Those who are farther away are fleeing the town. Some people are so scared they’re trying to leave anyway even if they are close to the fire,” Abu Ansa told Reuters by telephone.

Activists in the western city of Hama said troops, police and militias had set up dozens of roadblocks, cutting neighborhoods off from each other.

Western and Arab nations who want Assad to relinquish power are preparing an explicit gesture of support for his opponents.

U.S. Secretary of State Hillary Clinton said the Friends of Syria meeting would show that his government was increasingly isolated and offer support for “the brave Syrian people.”

“We’ll send a clear message to Russia, China and others who are still unsure about how to handle the increasing violence but are up until now unfortunately making the wrong choices,” Clinton said in Mexico at a meeting of the G-20 world powers.

Clinton is trying to ramp up diplomatic efforts against Assad’s regime on a trip to North Africa this week, as some countries begin to explore the possibility of arming Syria’s rebels.

The Secretary of State is traveling to London on Wednesday for a conference on Somalia, but U.S. officials will be using the international gathering to lay the groundwork for a major conference on Syria’s future taking place later this week in Tunisia. The trip comes as the Obama administration is opening the door slightly to international military assistance for Syria’s armed opposition.

One firm ally of Assad is Iran. Iranian television reported on Monday that two Iranian warships had docked in Syria to provide training for Syrian naval forces. Washington said on Tuesday it had no indication that the report was true.

The Syrian government reportedly has ordered large numbers of troops to deploy in Damascus in an attempt to prevent the spread of demonstrations to the capital city.

The International Committee of the Red Cross (ICRC) told Reuters that it was negotiating with Syrian authorities and opposition fighters on a “cessation of fighting” to bring life-saving aid to civilians hardest hit by the conflict.

Diplomatic sources said the ICRC was seeking a two-hour halt of hostilities in hotspots including Homs, a major industrial centre and Syria’s third largest city, next to Damascus and Aleppo. In some areas of Homs, the Free Syrian Army rebels set up checkpoints to try and block access to soldiers and Shabbiha militia loyal to Assad.

But activists still feel they have failed to draw the world’s attention. Foreign powers have yet to take measures to stop the killings, they say, or even allow safe passages to evacuate women and children and the critically wounded.

Anger is also rising against the Syrian opposition, who residents say have stood by and watched the slaughter. “We feel that the opposition has let us down ... Everybody is fooling us and using us for their own interests and we are the ones paying the price,” an activist calling himself Marx said.

Khaled Abu Salah, an activist in Baba Amro, sent a distress call to the main opposition group the Syrian National Council, comparing his city’s suffering to the violent suppression of a 1982 Islamist uprising in Hama, when forces loyal to Assad’s father killed at least 10,000 people. “We are being bombarded and we are dying. We are living the 80s with all its scenarios and until now you have done nothing,” he said in a YouTube video, standing in front of a shelled house.

“We hold you fully responsible. The people said that the SNC represent us and the people will delegitimize you [if you do nothing],” he said.