U.S. strikes on Iranian-linked targets in Iraq and Syria, which came in response to the deaths of three U.S. soldiers in a drone attack in Jordan, pose a significant threat to peace in an already volatile Middle East and are likely to exacerbate tensions in the region, experts say.

As many as 23 fighters, including nine Syrians, were killed in the U.S. attacks on Iranian strongholds in Syria's eastern province of Deir al-Zour on Friday night and into Saturday morning. Sixteen people, including civilians, were killed by the U.S. air strikes on the paramilitary Hashd Shaabi forces in Iraq.

Following the attacks, the Syrian Foreign Ministry on Saturday lashed out at the U.S. administration, accusing Washington of being a primary source of global instability.

On Saturday, Hashd Shaabi said in a statement that the air strikes on Friday night were "a blatant aggression" on its headquarters in the al-Qaim area, and stressed the number of casualties could rise as efforts to remove debris are still underway and the search for bodies continues.

Iraqi President Abdul Latif Rashid said in a statement on the same day that the air strikes represent a flagrant violation of Iraq's sovereignty and came as Iraq has shown a clear desire to organize the work of the international coalition through a round of discussions.

Meanwhile, the Iraqi Foreign Ministry summoned the U.S. charge d'affaires in Baghdad and handed him a protest note, in which Iraq expressed its rejection and condemnation of the U.S. air strikes.

The Iranian-backed al-Nujaba Movement said in a statement that it will retaliate against the U.S. "with what it deems appropriate at the time and place it wants."

Experts say that the attacks signify growing tensions arising from the Gaza conflict and threaten to destabilize the region.

Osama Danura, a political expert based in the Syrian capital Damascus, said the attacks are consistent with a pattern of conduct that the U.S. has adopted.

Instead of addressing the Gaza conflict diplomatically and politically, the U.S. has escalated the conflict through hostility, endangering peace in the already volatile Middle East, he said, adding such actions undermine international peace by prolonging the confrontation in the region and beyond. 

The United Nations Security Council will hold a meeting on Monday afternoon to discuss the threat to peace and safety created by the U.S. strikes on Syria and Iraq.

The strikes on Friday and Saturday are the first in a multi-tiered response by U.S. President Joe Biden's administration to the attack by Iran-backed militants on a U.S. base in Jordan, and more U.S. military operations are expected in the coming days.

Niu Xinchun, a professor at Ningxia University's China-Arab Research Institute, said the U.S. strikes in Iraq pile pressure on the Iraqi government and make the country more volatile.

It's challenging for the Iraqi government to mediate between Iran, the U.S. and Iranian-backed Iraqi militia, and Iran and Iraqi militia will fight back in the coming days, Niu said.

Su Xiaohui, associate research fellow at the China Institute of International Studies, warned that further attacks will increase tensions.

On the one hand, the U.S. military emphasizes its own security, and on the other hand, it is stirring up the situation in the Middle East, which in turn threatens its own security, Su said.

(With input from agencies)