In response to recent attacks on American forces, the United States conducted strikes against two Iran-linked sites in Syria on Sunday, according to Defense Secretary Lloyd Austin.

Meanwhile, nine people affiliated with Iran-backed groups in Syria were believed to have been killed in the strike on the eastern city of Deir Ezzor, a war monitor said.

"Nine people working for Tehran-backed groups were killed in US strikes on sites used by pro-Iran groups," Rami Abdel Rahman, who heads the Syrian Observatory for Human Rights, told AFP.

This marks the third occasion in less than three weeks that the US military has targeted locations in Syria with alleged ties to Iran. The strikes are part of a broader effort to address attacks on US forces in the Middle East, with more than 45 incidents reported since October 17, resulting in injuries to dozens of US personnel.

"US military forces conducted precision strikes today on facilities in eastern Syria used by Iran's Islamic Revolutionary Guard Corps (IRGC) and Iran-affiliated groups in response to continued attacks against US personnel in Iraq and Syria," Austin said in a statement.

"The strikes were conducted against a training facility and a safe house near the cities of Albu Kamal and Mayadeen, respectively," he said.

The US military previously targeted a Tehran-linked weapons storage site in Syria on Wednesday and hit two facilities on October 26, claiming affiliation with Iran and associated organizations. Despite these actions, the US asserts that none of the prior strikes resulted in casualties.

The US says the strikes were aimed at deterring attacks on its forces in Iraq and Syria -- more than 45 since Oct 17 -- that have wounded dozens of its personnel.

The recent surge in attacks on US troops is believed to be linked to the ongoing conflict between Israel and Hamas. The conflict initiated when the Palestinian group conducted a cross-border attack from Gaza on October 7, leading to Israeli officials reporting approximately 1,200 casualties.

In response, Israel launched a comprehensive air, land, and naval assault on Gaza, resulting in over 11,100 reported deaths so far, according to the territory's health ministry.

The United States, with roughly 2,500 troops in Iraq and around 900 in Syria, aims to prevent the resurgence of the Islamic State group. The recent developments have also had implications beyond Iraq and Syria, as the Iran-backed Houthi rebels in Yemen claimed to have shot down a US drone engaged in "hostile surveillance and espionage activities" in Yemeni territorial waters, purportedly in support of Israel.

Senior US officials confirmed the downing of the drone, emphasizing the US military support to Israel and the reinforcement of American forces in the region following the October 7 attack.