The US Defense Department says Secretary of Defense Lloyd Austin has pledged US support for Israel amid the possibility of Iranian retaliation for an airstrike on its embassy in Syria.

The Pentagon said that Austin spoke over the phone with his Israeli counterpart Yoav Gallant on Thursday.

It said Austin reiterated "ironclad US support for Israel's defense in the face of growing threats from Iran and its regional proxies."

The defense department also said Austin assured Gallant that "Israel could count on full US support to defend Israel against Iranian attacks."

Their talks came as Iran is hinting at a retaliatory attack following an airstrike on its embassy in Syria which was believed to have been carried out by Israel.