Damascus: The United States has denounced Russia’s policy of aiding the Syrian regime as “morally bankrupt,” as tensions between Damascus and Ankara escalate over cargo seized from a Syrian passenger plane.

US State Department spokeswoman Victoria Nuland refused to disclose to reporters what exactly had been in the cargo seized in Turkey on Wednesday, but said “we have no doubt that this was serious military equipment,” aimed at bolstering the Syrian regime.

Russian Foreign Minister Sergei Lavrov said, however, that the Syrian Air plane intercepted by Turkey on a flight from Moscow to Damascus was carrying a cargo of dual-purpose radar equipment, and insisted Russia did not violate any laws.

“This cargo is electrical technical equipment for radar stations, this is dual-purpose equipment, but is not forbidden by any international conventions,” Lavrov said.

Nuland acknowledged that Russia had not violated any embargo on Syrian President Bashar Al Assad and his government, but said “the policy’s still morally bankrupt”.

“Everybody else on the Security Council is doing what it can unilaterally to ensure that the Al Assad regime is not getting support from the outside,” she said in Washington.

“We have been saying for almost a year now, that no responsible country ought to be aiding and abetting the war machine of the Al Assad regime.”

As fighting raged on the ground, the tensions between Syria and Turkey grew.

Turkey scrambled a fighter jet on Friday after a Syrian helicopter attacked the rebel-held town of Azmarin near the border, an official in Ankara told AFP.

The Syrian foreign ministry accused Turkish Prime Minister Recep Tayyip Erdogan of lying when he said the jet intercepted on Wednesday was carrying Russian military equipment.

Turkey’s allies have warned of the risks embedded in the Syria conflict between the neighbours, which have exchanged cross-border fire amid fears the civil war could spark a regional conflagration.