Secretary of State Rubio says the U.S. is "very concerned" by expanding Israeli strikes targeting Syria's new government, and he wants "the fighting to stop."

The Israel Defense Forces (IDF) said the Damascus headquarters served as a command center for deploying regime forces to Suwayda, a southern Syrian region gripped by days of deadly clashes between government troops, Druze militias, and Bedouin groups.

Israel carried out a series of powerful strikes on the Syrian capital Damascus Wednesday, escalating a campaign it says is in support of an Arab minority group involved in deadly clashes with Syrian government forces.

Syrian troops are trying to intervene in sectarian violence in the south between the Druze minority and Bedouins. Israel said its strikes were to protect the Druze.

The Israeli military said it had "struck the entrance gate" of the Syrian regime's military headquarters complex in Damascus.

Israel bombed the Syrian army headquarters in Damascus on Wednesday after warning the Islamist-led government to leave the Druze minority alone in its Sweida heartland, where a war monitor says sectarian clashes have killed nearly 250 people.

Israeli Prime Minister Benjamin Netanyahu has said Syrian government troops will be blocked from the area south of the capital Damascus to protect the Druze minority following Israel's attacks in the country earlier this week.

THE HAGUE (Reuters) -Israeli airstrikes on Damascus are hampering Syria's efforts to find and destroy chemical weapons stockpiled during the rule of toppled ruler Bashar al-Assad, a government adviser said on Thursday.