Beirut, Jan 3 (AFP) The Syrian government on Friday condemned the killing of top Iranian and Iraqi commanders in a US strike which was hailed by the opposition.

The strike outside Baghdad airport killed top Iranian commander Qasem Soleimani and the deputy chief of Iraq's pro-Iran paramilitary organisation, Abu Mahdi al-Muhandis.

Syria is "certain that this cowardly US aggression... will only strengthen determination to follow in the path of the resistance's martyred leaders," a foreign ministry official was quoted as saying by the state news agency SANA.

The official described the killings as "a serious escalation of the situation" in the region and accused the United States of resorting to "the methods of criminal gangs".

The unnamed official said the strike was "part of the (US) policy aiming to create tensions and fuel conflict in countries in the region."

Soleimani had been a key backer of President Bashar al-Assad and helped him save his position after an uprising that began in 2011 threatened to topple his regime.

He was Iran's pointman in organising Iranian forces and their Shiite-dominated foreign proxies on the Syrian battlefield and a frequent visitor to Damascus.

Assad sent a letter of condolences to Iran's supreme leader Ali Khamenei, in which he praised Soleimani for his continued support.

The Syrian people "will not forget that he stuck by the side of the Syrian Arab army", Assad said.

"The memory of the martyr Soleimani will remain immortal in the conscience of the Syrian people," he added.

Thanks to the support of Iran and its proxies as well as to the decisive 2015 military intervention of Russia, Assad has clawed back most of the territory he lost in the early stages of the war.

In the few areas still that still escape the regime's control, some Syrians celebrated the death of a man they hold responsible for thousands of civilians deaths.

During a weekly Friday protest in the northwestern city of Idlib, one demonstrator held a placard that read: "We rejoice in the death of the terrorist Qasem Soleimani. Thank you Trump."

"This piece of good news will encourage us to keep advancing, God willing, the revolution will continue and the revolution will triumph," said another protester, who gave his name as Mohamed Shkeib.

Others handed out sweets to celebrate Soleimani's death.

Leaders of Syrian opposition groups for their part hailed the death of a man they blame for thousands for thousands of deaths in the nearly nine-year-old civil war.

"The murder of Qasem Soleimani, the number one perpetrator of Revolutionary Guards' crimes against the people of Syria and Iraq, is a blow that confirms that the world is able to stop Iran and protect Syrian civilians if it wants to," Nasr Hariri, a senior political opposition leader, said.

Ahmed Ramadan, another senior opposition figure, also praised the US strike.

"The killer of Syria's children has been killed, the killer of Iraq's free people has been killed," he said in a post on social media. (AFP)

(This is an unedited and auto-generated story from Syndicated News feed, LatestLY Staff may not have modified or edited the content body)