The Red Cross Saturday failed to agree a deal to evacuate wounded Syrians and Western journalists from battered Homs city as regime forces killed dozens more civilians on the eve of a constitutional referendum.
President Bashar al-Assad's forces resumed shelling the Baba Amr district of Homs after an apparent pause to allow in relief teams, more than three weeks into a deadly assault on rebels in Syria's third largest city.
Security forces killed at least 68 civilians nationwide, including 24 in Homs, said the Britain-based Syrian Observatory for Human Rights.
Twenty-three members of the regime's forces were killed across the country in clashes with army deserters siding with the rebels. Three army deserters were believed to have died in Alep and Deraa.
In Homs, the International Committee of the Red Cross said negotiations with the authorities and opposition groups to resume evacuations from Baba Amr, where two wounded Western journalists are trapped along with the bodies of two killed colleagues, failed.
But ICRC spokesman Saleh Dabbakeh told AFP the Red Cross would pursue its efforts.
The "ICRC and Syrian Arab Red Crescent have been negotiating since this morning with both the Syrian authorities and opposition groups in Homs. The discussion has yielded no concrete result today. Unfortunately, therefore, no emergency evacuation will take place today," he said.
"The ICRC and the SARC will continue to negotiate with the authorities and opposition in an attempt to enter Baba Amr and carry out life-saving evacuations."
A Western diplomat said the talks foundered because of "deep mistrust between the two sides" -- the Syrian authorities and the opposition.
"This is making the negotiations very arduous," said the diplomat.
A female Western journalist involved in Saturday's negotiations told AFP that ambulances entered rebel stronghold Baba Amr twice in the afternoon but were blocked by the Free Syrian Army.
"At one point they said they could not allow more evacuations, including those of foreign journalists, because nine people evacuated on Friday had been arrested," she said on condition of anonymity.
She said the ICRC investigated the rebel claim and reported that the charge that evacuees had been arrested "were totally false."
Dabbakeh earlier confirmed that the Red Cross and Red Crescent evacuated seven Syrians wounded in shelling on Friday, as well as 20 sick women and children. They were taken to Homs' Al-Amine hospital.
On Friday 11 ambulances and other vehicles entered Baba Amr, but only three ambulances left with injured Syrians, in the first rescue operation in the three-week onslaught on Homs.
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American reporter Marie Colvin and French photojournalist Remi Ochlik were killed on Wednesday when a rocket hit a makeshift media centre in Baba Amr.
French reporter Edith Bouvier and British photographer Paul Conroy suffered leg wounds in the attack.
A Syrian official, quoted by SANA state news agency, accused Baba Amr rebels of refusing to hand over Bouvier and the bodies of the journalists to rescuers.
"The concerned authorities in Homs, moved by humanitarian considerations, sent several local officials and Red Crescent ambulances to evacuate the Western journalists who entered Syria illegally," the official said.
"Despite efforts that lasted several hours, armed groups in Baba Amr refused to hand over the wounded woman (Bouvier) and the two bodies, thus endangering the life of the wounded French journalist."
France has intensified diplomatic efforts to rescue the wounded journalists, foreign ministry spokesman Bernard Valero told AFP.
With the violence showing little sign of easing, Syrians have been called to vote on Sunday on a new constitution aimed at appeasing protesters and fending off growing global pressure on Assad to step down.
But the referendum on the constitution, which could end five decades of Baath party rule, has already been dismissed by the United States as "laughable."
In the Tunisian capital on Friday, representatives of some 60 governments gathered for the first meeting of the "Friends of Syria" group expressed "strong concern" about the humanitarian situation.
The group said it would deliver humanitarian supplies immediately, if the regime ended the violence.
It also called for a "political solution" to the crisis and recognised the Syrian National Council, the main opposition coalition, as "a legitimate representative of Syrians seeking peaceful democratic change."
Information Minister Adnan Mahmud took a poetic swipe at the Friends of Syria meeting, calling it a gathering of the "friends of Washington and the enemies of Syria."
"Participants took only one decision, to continue supporting the terrorists and furnish them with weapons to attack the security and stability of Syria," he told reporters.
And China's Xinhua state news agency accused the United States and Europe of "harbouring hegemonistic ambitions" in Syria.
Beijing and Moscow, which have so far frustrated efforts to rein in Assad's regime by vetoing UN Security Council resolutions against Syria, boycotted the Tunis meeting.