Attempts by the Red Cross to evacuate more people trapped in the Baba Amr suburb of the Syrian city of Homs have stalled, with reports of more deaths from shelling.
The organisation had been in negotiation with the Syrian authorities but had made no progress by nightfall.
It evacuated several people on Friday but not two injured Western reporters.
Activists say 50 people died in unrest across Syria on Saturday, nearly half of them in Homs.
The BBC's Jim Muir in neighbouring Lebanon says that, throughout the day, the International Committee of the Red Cross (ICRC) and Syrian Red Crescent officials had tried to negotiate another evacuation of seriously wounded people from Baba Amr.
This included the two Western journalists, Edith Bouvier and Paul Conroy, as well as the bodies of another two journalists, Marie Colvin and Remi Ochlik, who were killed last week.
ICRC spokesman Hisham Hassan said: "Unfortunately we will not be able to enter Baba Amr today (Saturday). We continue our negotiations, hoping that tomorrow we will be able to enter Baba Amr to carry out our life-saving operations."
He said the Syrian Arab Red Crescent had continued to carry out evacuations in other areas of Syria, including two in other neighbourhoods of Homs.
Activists said 11 people were killed on Saturday by renewed shelling in Baba Amr, which has borne the brunt of the army bombardment of Homs that began last month.
Hundreds of armed rebels from the Free Syrian Army are holding out in the suburb.
In Khalidieh, a district close to Baba Amr, thousands of mourners packed a square and chanted anti-regime slogans as six coffins were paraded around in a circle. They were of people killed in the latest violence.
In addition to the deaths in and around Homs, the Syrian Observatory for Human Rights also reported that:
- Security forces shot dead six people in Ezaz in Aleppo province
- Some 4,000 people took to the streets in Aleppo itself to mourn a protester killed on Friday
- Six civilians were killed in the villages of Maarazaf and al-Majdel, in Hama province
- Sixteen members of the security forces were killed in clashes with rebels across the country
Meanwhile, international pressure is mounting on President Bashar al-Assad to end his government's 11-month crackdown on opponents.
Kofi Annan, the former UN secretary general who has been appointed the UN and Arab League's envoy to Syria, called for all parties to co-operate in finding a peaceful solution to the crisis.
On Friday a meeting of the "Friends of Syria" group was held in the Tunisian capital, Tunis.
Delegates from 70 countries issued a declaration calling on the Damascus government to end violence immediately, allow humanitarian access, and permit the delivery of relief supplies.
The UN estimated in January that 5,400 people had been killed in the conflict. Activists say the death toll now is more than 7,300.
The Syrian regime restricts access to foreign journalists and casualty figures cannot be verified.