By Khaled Yacoub Oweis and Dominic Evans
AMMAN/BEIRUT (Reuters) - Twin bomb blasts hit Syrian military and security buildings in the northern city of Aleppo on Friday, killing 25 people in the worst violence to hit the country's commercial hub in the 11-month uprising against President Bashar al-Assad.
Mangled, bloodied bodies as well as severed limbs lay on the pavement outside the targeted buildings, as shown in live footage on Syrian television, which consistently portrays the revolt against Assad as the work of foreign-backed "terrorists."
No one claimed responsibility for the attacks in Syria's second city, as officials put the total death toll in the two blasts at 25. But they came as Assad's forces grow more ferocious in operations to stamp out the popular uprising.
On another front, army tanks massed outside opposition neighborhoods in the western city Homs on Friday morning after a week of bombardments that have killed dozens of civilians and drawn condemnation from world leaders.
Activists in Homs said shelling resumed sporadically in the morning and they feared a big push was imminent to storm residential areas of the city that has come to symbolize the plight of the anti-Assad movement.
The unrelenting bloodshed only highlighted the difficulties that Western and Arab powers faced in trying to resolve the crisis in a country which has a key place in the strategic balance in the volatile Middle East.
Bolstered by Russian support, Assad has ignored appeals from the United States, Turkey, Europeans, fellow Arabs and other governments to halt the repression and to step down.
Foreign ministers of the Arab League, which suspended a monitoring mission in Syria last month because of the violence, will discuss a proposal to send a joint U.N.-Arab mission to Syria when they meet in Cairo on Sunday, a League official said.
EU URGES RUSSIA
The European Union's foreign policy chief added her voice to international calls for Russia, Syria's strongest ally, to support a United Nations resolution demanding Assad halt the crackdown. But Russia, with a recent history of sending tanks into its own rebel cities, has said no one should interfere in the country's affairs.
"My message to my Russian colleagues is that they too need to recognize the reality of the situation on the ground and we can't go on simply allowing this to happen," the EU's Catherine Ashton said during a visit to Mexico.
But having ruled out intervening military, as NATO did decisively in Libya nearly a year ago, the foreign powers arrayed against Assad have few good cards to play.
Many analyst believe that although the uprising has evolved from peaceful street demonstrations into an armed insurgency, Assad can count on a powerful military and a certain degree of popular support to survive for several months before he might join the list of deposed Arab leaders like Libya's Muammar Gaddafi and Egypt's Hosni Mubarak.
The fragmented leadership of the revolt also poses problems for those who would support it.
The Aleppo blasts contrasted with the carnage in Homs that has gripped world attention in recent days and played into the government narrative that it is only defending the state against violent foes.
In a live television report, a correspondent lifted blankets and plastic sheets which had been laid over corpses on the pavement to show a body with its head blown off. Other bloodied human remains included a limbless torso and a severed foot.
"We apologize for showing these pictures, but this is the terrorism which is targeting us," the reporter said.
Private Addounia Television said 11 civilians and security force members were killed in the explosion at a military security building and six more at a base for security forces. State television later quoted the Health Ministry saying a total of 25 were killed and 175 wounded in the two blasts.
A concrete wall around one building was badly damaged and its windows were blown out. At least one car appeared blackened and destroyed and several more were damaged.
The TV reporter said children were among the dead, showing a single roller skate left on the pavement.
"Is this the freedom of Hamad and Erdogan?" one man shouted, referring to Qatari Prime Minister Sheikh Hamad bin Jassim and Turkey's Prime Minister Tayyip Erdogan, who have led the chorus of regional criticism against Assad. "Hamad, you dog," he said.
Aleppo, Syria's main commercial city close to the northern border with Turkey, had been spared most of the bloodshed which has hit other parts of the country during the uprising against 42 years of dynastic Assad family. But it has seen increasing protests and violence in recent weeks.
AWAITING AN ONSLAUGHT
Meanwhile in besieged Homs, activists said shelling began again in the morning. Outgunned rebels loosely grouped under the Free Syrian Army were preparing to counter an onslaught.
In a message of defiance during the overnight lull, activists staged a rally against Assad in the Homs neighborhood of al-Bayada. YouTube footage showed hundreds of youths holding hands and dancing to the tune of a songs chanted by Abdelbasset Sarout, a 22-year-old soccer star turned activist.
"You oppressor, go ... Great Homs, Syria will be free," Sarout sang from a makeshift stage while white and green rebel flags fluttered overhead.
Activist Mohammad Hassan said the brief respite in the shelling had allowed him to leave his basement and survey the extent of the damage: "There isn't one street without two buildings or more that are badly damaged from the shelling," he said by satellite phone.
Artillery barrages had been directed at Baba Amro, Inshaat, Khalidiya and other districts of the city where rebels have been lying low while mounting hit-and-run guerrilla attacks on the rear of Assad's troops, he said.
"Four tanks or armored vehicles were destroyed today on the edge of Baba Amro and some bread and medical supplies were delivered there for the first time in days by activists who crossed from Brazil Street," Hassan said.
Witnesses said makeshift hospitals in Homs were overflowing in the besieged areas with the dead and wounded from nearly a week of government bombardments and sniper fire.
Medical supplies and food were running out and, in the streets, some of the wounded had bled to death as it was too dangerous for rescuers to bring them to safety.
The Local Coordination Committees, an opposition group in Homs, put the death toll on Thursday alone as high as 110 by nightfall, though it remains impossible to verify such accounts.
(Writing by Angus MacSwan; Editing by Alastair Macdonald)