The United States is deploying around 9,000 additional troops to the Middle East as President Donald Trump weighs the possibility of renewed strikes on Iran, a US official said on Thursday. The deployment comes amid continued tensions between Washington and Tehran and growing signs that the US could take further military action against Iran.

The new deployment includes more than 7,000 sailors and 2,000 Marines aboard a group of US ships moving towards the region. The forces will add to the growing American military presence in the Middle East, with hundreds of aircraft also supporting the deployment.

The ships include the USS Theodore Roosevelt carrier strike group and the USS Makin Island amphibious readiness group. Their arrival could bring the number of US aircraft carriers operating in the region to three by the end of October, according to the US official. The official spoke anonymously due to the sensitivity of the military movement.

The latest deployment would take the number of US sailors and Marines in the Middle East to more than 20,000. Two other carrier strike groups, the USS George H.W. Bush and USS George Washington, are already operating in the region. The USS Boxer amphibious readiness group is also present.

Trump has also raised the possibility of Iranian involvement in an alleged attack linked to a flydubai flight bound for Israel. In the incident, a co-pilot allegedly attacked the captain before passengers intervened and helped prevent the aircraft from crashing.

Trump told reporters at the White House that initial information indicated a possible Iranian connection to the incident. “I would say the answer, based on what I’m hearing, is yes, but we’re working on it right now," Trump said when asked about a possible link to Tehran.

Trump warned that Iran could face a strong military response if its involvement in the incident is confirmed. “Oh, they’ll be hit very hard, don’t worry," Trump said.

Trump also told Time magazine that renewed US bombing of Iran was “possible" after the November 3 elections. He did not provide details about any possible military plans.

The US military build-up comes as Washington and Tehran remain locked in heightened tensions. Trump has also said he rejected a recent Iranian ceasefire proposal. The offer included reopening the strategically important Strait of Hormuz, but Trump said the proposal did not go far enough.