What meaning Tehran took from the attack on its proxies remains unclear.
Middle East experts said the military endeavor may have also been meant to establish the administration's firm stance as it attempts to restart talks about the 2015 global nuclear deal that was abandoned by the Trump administration.
Foreign ministry spokesman Saeed Khatibzadeh said the strikes by "the new U.S. administration [would] lead to intensifying military conflicts and further destabilize the region".
Asked Friday by reporters what message he intended for Iran in authorizing the operation, Biden said: "You can't act with impunity".
Pentagon spokesman John Kirby said two F-15E "Strike Eagles" dropped seven precision-guided munitions, totally destroying nine facilities and partially destroying two facilities.
Militiamen fled from six of the seven buildings hit in the strikes after spotting what they believed to be a USA surveillance aircraft, according to the Sabareen news channel on Telegram, which is used by Iran-backed groups.
Due to an ongoing assessment of the damage from the strike, Kirby would only say preliminary reports show some causalities at the site, but he would not offer information on how many. Bernie Sanders, I-Vt., said in a statement Friday, adding in a tweet he was "very concerned by last night's strike by US forces in Syria". In a statement, the Iraqi Defense Ministry pushed back against what appeared to be a suggestion from Defense Secretary Lloyd Austin that Iraq shared intelligence with the US government before the strike.
Russian Federation has been fighting alongside Syrian government forces in the country's nine-year civil war, clashing repeatedly with US forces and USA -allied Kurds who have been battling the terror group Islamic State on the same battlefield.
U.S. lawmakers have asked the administration of President Joe Biden to provide legal justification for its decision to launch air strikes on military targets in Syria, amid growing complaints of overreaching presidential war powers enacted after the attacks of September 11, 2001.
"We in Congress have congressional oversight in engaging in war and we haven't been briefed yet and we have not authorized war in Syria", Omar told CNN. As a matter of global law, the U.S. acted pursuant to its right to self defence as reflected in Article 50-1 of the UN Charter. The U.S. Navy blamed the incidents on Iran, which denied involvement.
He said Iraqi and Kurdish partners had provided intelligence that led to the identification of the groups behind the rocket attacks. In a statement, it said the Biden administration "is supposed to stick to worldwide legitimacy, not to the law of the jungle as [did] the previous administration". Russian Foreign Minister Sergey Lavrov said the US informed Russia of the strike just minutes before it was carried out.
Sen. Chris Murphy, D-Conn., noted that the president has the right to defend the nation and its armed forces from imminent attack, but called the recent airstrikes in Syria "unacceptable". "As a matter of global law, the United States acted pursuant to its right of self defense, as reflected in Article 51 of the U.N. Charter".
White House Press Secretary Jen Psaki defended the action as "necessary", and said Biden "has the right to take action" as he sees fit. Hussein is one of several Iraqi officials who have traveled to Iran in recent months to try to persuade it to use its influence to rein in militia forces. "Iran supports an entire constellation of terrorist groups that stretches from Yemen to Iraq, Syria, and Lebanon, right to the borders of Israel".
Iran is believed to be searching for an opportunity to avenge the U.S. assassination of top general Qasem Soleimani early previous year.
"These groups are decentralized", he said.