The Red Cross delivered emergency aid to areas around the battered Baba Amro district of the Syrian city of Homs on Sunday, but was blocked for a third day from entering the former rebel bastion amid reports of bloody reprisals by state forces.
Activists reported shelling and other violence across Syria, sending one of the biggest surges of refugees across the border into Lebanon in a single day since a revolt against President Bashar al-Assad began a year ago.
Concerns mounted for civilians stranded in Baba Amro in freezing weather with little food, fuel or medicine after weeks in a state of siege and under near-constant shelling by Syrian forces intent on crushing the uprising.
We have the green light, we hope to enter, we hope today is the day, said the International Committee of the Red Cross' Damascus-based spokesman Saleh Dabbakeh, declining to comment on what he said were sensitive talks with Syrian officials.
We are very concerned about the people in Baba Amro.
The ICRC said it had been prevented from entering Baba Amro by Syrian forces despite receiving government permission, a move activists said was to hide massacres by the Syrian army.
U.N. Secretary-General Ban Ki-moon said on Friday he had received grisly reports that troops were executing and torturing people in Homs after insurgents abandoned their positions.
Aid workers began delivering supplies to areas near Baba Amro where people had fled, the ICRC said.
It is a positive step. But we want to enter Baba Amro today, ICRC spokesman Hicham Hassan told Reuters in Geneva.
The United Nations' refugee agency said up to 2,000 Syrians had fled the fighting for neighbouring Lebanon.
We had similar numbers in April 2011, but the flow of new arrivals had stabilised since then, United Nations refugee agency spokeswoman Dana Sleiman said.
Refugees told Reuters of army shelling and gunfire on border towns. One woman said she and her family had fled the village of Jusiyah, near Qusair, some 12 km (7 miles) from the border.
In the morning the shelling started, so we had to leave towards Lebanon. There were some wounded, but I don't know what happened to them, said Um Ali, 64.
She was sat under a tree with her husband, five sons and a pregnant daughter-in-law. They had not brought any belongings.
We don't know what to do, she said.
The outside world has proved powerless to halt the killing in Syria, where repression of initially peaceful pro-democracy protests sparked an insurrection by army deserters and others.
The government says it is fighting foreign-backed terrorists it blames for killing hundreds of soldiers and police across the country.
Syrian state television showed the gory corpses of anti-Assad fighters killed in clashes in the suburbs of the city of Hama, as well as an array of captured weapons, including arms it said were U.S. and Israeli-made.
In a sign of mounting chaos, one activist reported that the Syrian army had raided a girls school in Daraya, near Damascus, beating students for holding an anti-Assad protest and threatening to open fire on similar demonstrations in future.
In a house in the Douma suburb of Damascus, the activist told Reuters by Skype that the Syrian army had killed two defectors and seven other people who had been harbouring them.
Other activists reported government raids in Hama in which one young man was shot dead, and heavy shelling in the town of Rastan, north of Homs, where rebels have been hiding.
Residents told me that shelling started early this morning shortly after helicopters and spotter planes were seen above the town, said Rami Abdelrahman, head of the Britain-based Syrian Observatory for Human Rights.
Clashes between Free Syrian Army defectors and Syrian troops were reported in Jebel al-Zawiya in Syria's north, and activists said government forces had used tear gas to end an anti-Assad protest of around 1,000 people in the northern city of Aleppo.
Abdelrahamn also reported an attack on a Syrian army weapons depot by rebels near Homs on Saturday, killing and wounding up to 50 Syrian troops. Activists' reports are difficult to verify independently due to Syrian reporting restrictions.
The United Nations says Syrian security forces have killed more than 7,500 civilians since the revolt against the Assad family's four-decade rule began in March last year.
The Syrian government said in December that armed terrorists had killed more than 2,000 soldiers and police during the unrest.
Lebanon deployed more troops to its northern border in response to the violence in Syrian towns nearby, a Reuters witness said, part of a conflict that risks dragging in regional powers with rival sectarian interests.
In the Lebanese capital, Beirut, hundreds of soldiers and scores of military trucks and jeeps blocked off the city centre during protests for and against Assad, whose ruling clan are Alawites, an offshoot of Shi'ite Islam.
Lebanon is mainly made up of Shi'ites, Sunnis and Christians, and is home to the powerful Shi'ite militant group Hezbollah, which is backed by Shi'ite Iran.
Sunni Arab states Qatar and Saudi Arabia have been among the loudest calling for Assad's downfall, and have even suggested arming his opponents.
We sacrifice our blood and souls for you Bashar, chanted a pro-Assad crowd of some 500 people. Some stepped on photos of Saudi Arabia's King Abdullah and threw shoes at a poster of him.
A similar sized anti-Assad crowd sang: We sacrifice our blood and souls for you, Homs.
Former Syrian ally Turkey said Assad was guilty of war crimes while China said it was deeply worrying that the situation in Syria remains grave.
China, which along with Russia has twice vetoed U.N. Security Council resolutions condemning Damascus, urged government and rebels to end the violence and start talks, but reiterated its opposition to foreign military intervention.
We oppose anyone interfering in Syria's internal affairs under the pretext of 'humanitarian' issues, said a foreign ministry statement carried by Xinhua news agency.
Russian Foreign Minister Sergei Lavrov will join Arab counterparts at a meeting in Cairo this month to discuss the Syrian crisis, the Arab League said on Sunday, a move that could indicate Moscow is shifting its stance on the issue.
(Additional reporting by Afif Diab on Lebanese border, Stephanie Nebehay in Geneva and Ayman Samir in Cairo; Writing by Mohammed Abbas; Editing by Robin Pomeroy)