BEIRUT — Syrian rebels on Thursday bombarded a military air base in Aleppo using a tank captured from government troops as activists reported the regime has launched new raids against opposition fighters near the capital Damascus, killing dozens.
It was one of the first indications the rebels are starting to deploy the heavy weapons they've managed to capture in the past weeks from the Syrian army. The Syrian Observatory for Human Rights said the rebel-seized tank shelled the Menagh military airport outside Aleppo, which the regime has used to launch attacks on rebel positions in the surrounding area.
The incident represents an escalation in the 17-month-old uprising in which an estimated 19,000 have died, since the rebels now can start trading tank shells with the heavily armed regime that also has fighter jets and helicopter gunships.
The rebels have also been buoyed by new announcements of assistance by the U.S., which said Thursday it was earmarking an additional $12 million for Syrian civilians, on top of the extra $10 million in "nonlethal assistance" it promised the day before to the opposition.
Prospects for a diplomatic solution grew even dimmer Thursday, however, when the U.N. special envoy to Syria, Kofi Annan, announced his resignation by the end of the month, effectively sinking a U.N. mission that had seen little success up until now to get either side to agree on a ceasefire.
Rebel forces in northern Syria attacked the country's largest city of Aleppo two weeks ago and have captured several neighborhoods, mostly lower income areas on the periphery, which they have since held despite ground and air assaults by the government.
Residents reported Thursday that Internet and mobile phones were barely working since the night before, which had raised fears of an imminent government onslaught on Aleppo. But the day only saw the usual clashes around the rebel bastion of Salaheddine and shelling, resident Abu Adel told The Associated Press. Communications also began to work again by late afternoon.
With its proximity to rebel-friendly Turkey just to the north, Aleppo has enormous strategic importance to the opposition and if the rebels were able to capture and hold it, the city could form the kernel of a wider rebel-controlled zone.
"If Aleppo falls, then automatically we are going to establish headquarters at the presidential palace," said Syrian opposition leader Burhan Ghalioun, late Wednesday in Paris. The comments appeared overconfident, given that the regime still wields considerable power. "Nothing more would stand in the way of the Free Syrian Army. Hama and Homs, to the outskirts of Damascus, have in large part been liberated."
The Syrian army, however, still has many more tanks and armored vehicles than the rebels and there was no indication that Thursday's attack on the air base was particularly effective. Later, a nearby village was shelled by government forces out of that same air base.
There was also heavy shelling earlier in the day around the town of Azaz on the Turkish border, which has been in rebel hands for weeks along with a checkpoint crossing in the area, making it easier to deliver rebel weapons and supplies to the Aleppo battle. It would be a huge blow to the opposition if the government retook the crossing.
In the capital Damascus, the regime on Thursday announced a string of raids against rebels in neighborhoods on the southern edge of the city the night before, killing and arresting "a number of terrorists," as the government refers to rebels.
Operations also took place in the well-to-do Muhajireen district on Thursday close to the presidential palace in Damascus. Activist Abu Qais, based in the Syrian capital, said 20 people were arrested.
Also on Thursday, the regime bombarded the southern suburb of Tadamon with artillery and mortars, sending plumes of smoke up into the sky, according to the Observatory. People in downtown Damascus confirmed hearing explosions coming from that direction and seeing the smoke.
A bold rebel assault on Damascus was crushed two weeks ago in fierce fighting, but the latest raids show that pockets of resistance remain in the capital and the surrounding countryside.
Abu Qais said that at least 20 people were killed by raids in the Yalda suburb on Wednesday night, in the south, while the Observatory reported that 47 people had been killed in the Jdaidat Artouz neighborhood to the southwest. Videos posted by activists show piles of bloody corpses, many with visible bullet holes. The videos could not be independently authenticated.
International condemnation of Syria's handling of the uprising is growing, but with President Bashar Assad protected by China and Russia in the Security Council, there has been no effective action in response.
Under pressure from Brazil, Russia, India and China, a General Assembly resolution sponsored by Arab countries and meant to condemn the regime was watered down to remove calls for Assad's departure. Any mention of sanctions was also removed.
The United Nations' Syria policy has been further hamstrung by the resignation of Annan, who first came up with the six point peace plan to resolve the crisis, including a cease-fire that was supposed to take effect in mid-April but never took hold.
The U.N. World Food Program, meanwhile, sounded the alarm Thursday over the humanitarian situation in Syria with close to 3 million people needing food and livestock assistance in the next 12 months — more than 10 percent of the country's population of 22 million.
The study carried out by the WFP as well as the Syrian Agricultural Ministry said the country's agricultural sector has lost $1.8 billion this year from damaged crops and livestock. It's not just the fighting that has kept farmers from their harvest but also shortages in fuel, electricity and labor to work the farms.
The statement warned that the country's poorest would be the hardest hit.
U.S. officials, however, said Thursday that the Obama administration will ramp up its humanitarian aid to Syrian civilians by $12 million, increasing the total to $76 million. The funds will go to U.N. agencies, the International Red Cross and other organizations doing relief work. The officials spoke on condition of anonymity because they weren't authorized to divulge the information.
A day earlier, State Department spokesman Patrick Ventrell told reporters that the U.S. had added $10 million to its "nonlethal assistance" supplies to the Syrian opposition, which includes communications equipment. The new total now stands at $25 million.
Syria's Foreign Ministry condemned the move, describing giving money to the opposition as "funding terrorism," in contravention of U.N. Security Council resolutions.
• Associated Press writers Zeina Karam in Beirut and Bassem Mroue in Kilis, Turkey, Peter Spielmann at the United Nations and Bradley Klapper in Washington, D.C., contributed to this report.