Syrian government forces have continued bombarding the city of Homs, ignoring calls from the International Committee of Red Cross for a two-hour daily truce to facilitate delivery of humanitarian aid to civilians trapped by the unremitting violence.
Syrian activists said at least 63 people had been killed across the country on Tuesday as troops loyal to President Bashar al-Assad used heavy tanks to attack opposition strongholds in Homs and raided the northern mountainous town of Jabal al-Zawiya in pursuit of army defectors.
The Local Coordination Committees, an opposition group, said more than 100 were killed on Tuesday, but the report could not immediately be confirmed.
The casualty figures could not be independently verified as foreign media faces stiff restrictions within Syria.
In-depth coverage of escalating violence across Syria
Activists said the government had been bolstering its forces outside Homs, apparently to storm the city after 18 straight days of siege.
"Government troops have been unable to advance because of stiff resistance from defectors inside,'' an activist in Homs told the Associated Press news agency on condition of anonymity, because of fears of government reprisal.
Residents and activists say the government's stepped up attacks on Baba Amr recently have left the district without enough food, water, medicine and electricity.
"They bombed all the water tanks on the roofs of buildings. There's no water. Some people have gone without bread for days,'' said Shaker, a Homs resident, who estimated the shells fell at a rate of about 10 per minute at some points in the siege.
More than 200 people were wounded, he said, adding that children were among the dead.
One Homs resident told AP that many people injured by the attacks are unable or too scared to go to the hospital for treatment because the government has taken control over medical facilities. He also said that some of those wounded are bleeding to death at home.
"My cousin is a doctor and he said they've given up on treating serious wounds. The numbers are too many to cope with especially with so little supplies," the resident said.
Activists also said troops had opened fire overnight to disperse a demonstration in the capital Damascus.
Protesters during the night also blocked the roads leading to Baramkeh Square in the centre of the capital, according to Mohammed Shami, a spokesman for activists in Damascus province.
He said demonstrators used "burning materials" to shut the roads, triggering a security alert that saw "heavily armed forces" deployed in the area in few minutes.
The demonstrators were acting as part of a "campaign of civil disobedience in Damascus in support of Homs and afflicted Syrian cities," Shami said in a statement.
The Red Cross said on Monday that it was in talks with the Syrian authorities and rebels to halt the violence so that it can deliver aid, amid calls to allow women and children out of Homs.
Saleh Dabbakeh, a Red Cross spokesman in Damascus, told Al Jazeera that they "were exploring several possibilities for delivering urgently needed humanitarian aid".
He did not give explicit details on who was taking part in the talks, saying only that they were ongoing.
"The content of the discussions with the Syrian authorities and all those involved in the fighting remains confidential," Dabbakeh said.
The announcement comes amid reports that Syria's opposition is to take part in an international conference in Tunis on Friday to which European Union and Arab League members as well as China, Russia and the US have been invited.
Earlier on Monday, Rafik Abdessalem, Tunisia's foreign minister, speaking after a meeting of Mediterranean region foreign ministers in Rome, Italy, said an agreement had been reached on the need to avoid "an Iraqi scenario" and preserve Syria's integrity.
"I don't think any Arab country is going to ask for military intervention [in Syria]. European countries don't want it either," Abdessalem said.
"We don't want an Iraqi scenario ... we have to preserve the integrity of Syria.
"We all agree on the need to urge the Syrian government to put an end to its suppression of demonstration. There are rights that should be secured for the people of Syria. They have a right to freedom and democracy."
Reversing an earlier position expressed on Friday, Abdessalem said: "The Syrian National Council [SNC], the largest Syrian opposition group and other opposition groups will be represented at the Tunis meeting."
Tunisia, which hosted a first international conference on Syria in December and broke off ties with the Assad government earlier this month, does not recognise the SNC as an official entity.
Giulio Terzi, the Italian foreign minister, said his country wanted the Arab League's plan for Syria to be implemented.
The Arab League has called for the UN to approve a joint Arab-UN peacekeeping force.
Earlier this month, China and Russia blocked a draft UN Security Council resolution that backed an Arab plan calling on Assad to step down.