DUBAI: Iran on Thursday condemned as inhumane a fresh round of US sanctions against its regional ally Syria and said it would expand its trade ties with Damascus.

The United States on Wednesday imposed its toughest sanctions targeting Syrian President Bashar al-Assad to choke off revenue for his government and force it back to UN-led negotiations on ending his country's war.

"As the world is involved with the Corona pandemic, the imposition of such inhumane sanctions will only exacerbate the suffering of the Syrian people," Foreign Ministry spokesman Abbas Mousavi told state media.

"We will continue our economic cooperation with the resilient Syrian nation and Syria's government, and despite these sanctions, we will strengthen our economic relations with Syria," Mousavi said.

Iran, which itself faces heavy US sanctions, is a close ally of Assad. Tehran has sent thousands of fighters to back the Syrian central government, including Iranian-trained Shi'ite militias whose members are from Afghanistan and other countries.