BEIRUT, Lebanon — As fierce fighting continued across Syria on Sunday, the country's foreign minister, on a visit to Iran, blamed Saudi Arabia, Qatar and Turkey for the escalation of violence and vowed that his government would rout the rebels fighting the army in Aleppo.
"Their plots will fail," said the minister, Walid al-Moallem. But, he added, that would not stop the "campaign on the international stage against Syria."
Moallem made his remarks as the Syrian government continued to pound neighborhoods in Aleppo, Syria's largest city, which has become the latest front in the bloody conflict. In recent days, as opposition fighters have moved to gain control of Aleppo's neighborhoods, the government has sent armored columns, troops and helicopters to meet them — preparing, residents fear, to move into the city.
On Sunday, activists reported more clashes, but said there had been no mass assault by the army, many of whose troops remained stationed on the city's outskirts.
Instead, activists said they had noted a change in tactics, saying that the government was using helicopters and artillery to attack several neighborhoods, rather than the tanks that had been deployed on Saturday.
Rebel commanders said they had destroyed several tanks. A Reuters reporter in Aleppo on Sunday reported seeing at least one heavily damaged tank and another one that appeared to have been captured intact.
Witnesses reported seeing entire neighborhoods emptied of residents, shops that had been closed and hospitals that had no doctors. Video posted on the Internet claimed to show a factory fire in Aleppo, a city that has been Syria's commercial capital. Residents were seen cheering in another video as what was said to be a captured tank paraded through the streets.
More than a dozen people were killed in the fighting, according to antigovernment groups. Agence France-Presse reported that Pierre Torres, a freelance journalist who had done work for the news agency, was wounded in the fighting and evacuated to Turkey on Sunday.
Moallem's visit to Iran, one of Syria's few remaining allies, underscored the pressure on his government as it fights a growing armed insurgency on several fronts. Emboldened by a bombing in Damascus this month that killed four senior government officials, rebel fighters have tried to gain ground in Syria's largest cities — Damascus, the capital, and Aleppo — testing the strength and reach of President Bashar Assad's army.
The conflict in Syria has increasingly drawn in foreign powers. As Syria's international isolation has grown, Western nations have accused Iran of continuing to provide Assad's government with weapons and other support. Russia, which has said it has suspended weapons sales to Syria, remains Assad's staunchest defender, blocking international efforts to remove him from power.
On the other side, Saudi Arabia and Qatar have led an effort to arm Assad's opponents. Turkey is said to have allowed weapons to move over its border, and U.S. intelligence officials have helped select the recipients, according to U.S. officials.
Moallem played down the domestic opposition to his government, saying that despite the "plot" by those countries — led, he said, by Israel — Syria did not need foreign help to defend itself.
At the same time, the leader of an opposition group suggested Sunday that the rebels would need heavier weapons.
"The rebels are fighting with primitive weapons," said the leader, Abdelbasset Sida of the Syrian National Council, according to Reuters. "We want weapons that we can stop tanks and planes with."
U.S. Defense Secretary Leon Panetta said Sunday at the outset of a five-day Mideast tour that Assad's use of helicopter gunships to counter a civil uprising will prove to be his demise.
While giving no indication that the Obama administration is contemplating military intervention, Panetta said it is increasingly clear that the Syrian crisis is deepening.
"If they continue this kind of tragic attack on their own people … I think it ultimately will be a nail in Assad's coffin," Panetta told reporters traveling with him from Washington. "His regime is coming to an end."