US embassies beefing up security ahead of Trump's expected announcement on Jerusalem

Several teams of U.S. Marines will reinforce security at some American embassies in the Middle East, according to U.S. officials, in advance of President Donald Trump's expected announcement that the U.S. embassy in Israel is moving to Jerusalem.

The U.S. military has made prudent precautionary planning in the Mideast region if violence flares up following Trump's expected announcement, according to several U.S. officials.

Trump is expected to officially recognize Jerusalem as the capital of Israel on Wednesday and initiate the process of relocating the U.S. embassy to the city from Tel Aviv, two U.S. officials and a source close to the White House confirmed to ABC News Tuesday.

U.S. officials said planning has been underway to send several Marine Fleet Anti-Terrorism Security Teams (FAST) to some American embassies in the region to reinforce their security postures in anticipation of the expected announcement.

"Due to operational security I won't get into specifics, but the Department of Defense takes necessary steps to mitigate threats to U.S. personnel and interests around the world," said Lt. Colonel Mike Andrews, a Defense Department spokesman.

"In addition, [the Department of Defense] continually works closely with State Department's Bureau of Diplomatic Security to protect U.S. interests at all embassies and consulates," he added.

The FAST teams consist of a platoon of about 40 Marines specially trained to assist with providing extra security at U.S. embassies. They are available on short notice to help other Marines providing security at U.S. embassies worldwide.

On Tuesday, the U.S. embassy in Israel warned American diplomats and their families that "until further notice" they were not to conduct personal travel in Jerusalem's Old City and the West Bank.

"United States citizens should avoid areas where crowds have gathered and where there is increased police and/or military presence," read a security message posted Tuesday on the embassy's website.

Turkish Minister of Foreign Affairs Mevlüt avusoglu, who was meeting with U.S. Secretary of State Rex Tillerson on Wednesday, warned the United States against making the decision. He also said he had told Tillerson personally it was a dangerous move.

"It would be a grave mistake," avusoglu told U.S. reporters while waiting for a photo op with Tillerson. "It would not bring any stability, peace, but rather chaos and instability."

ABC News' Conor Finnegan contributed to this report.