Syria was once among the closest allies of the Islamic republic, but the new government resents Tehran’s support for the Assad regime and has pledged not to allow attacks on Israel from its territory.

The conflict has killed hundreds and wounded more than a thousand since Friday in Iran and killed at least 24 and injured hundreds in Israel. The attack on Iran came amid protracted talks between the U.S. and Iran centered around Iran’s nuclear program.

Oman and Qatar were leading efforts to begin ceasefire talks, while mediators said Iran was open to resuming nuclear negotiations if Israel’s attacks stop.