WASHINGTON, Apr. 11 (Reuters) - The United States said on Thursday it had restricted its employees in Israel and their family members from personal travel outside the greater Tel Aviv, Jerusalem and Be'er Sheva areas amid Iran's threats to retaliate against its regional adversary.

Iran has vowed revenge for the April 1 airstrike on its embassy compound in Damascus, ratcheting up tension in a region already strained by the Gaza war.

"Out of an abundance of caution, U.S. government employees and their family members are restricted from personal travel outside the greater Tel Aviv (including Herzliya, Netanya, and Even Yehuda), Jerusalem, and Be'er Sheva areas until further notice," the U.S. embassy said in a security alert, opens new tab on its website on Thursday. "U.S. government personnel are authorized to transit between these three areas for personal travel."

Washington has a policy of informing all American citizens via such warnings when it updates security measures for its personnel in a country.

U.S. President Joe Biden said on Wednesday Iran was threatening to launch a "significant attack in Israel," and that the U.S. remained committed to its ally's security.

Asked about the security alert, State Department spokesperson Matthew Miller noted that Iran had been making public threats toward Israel.

"We conduct ongoing assessments all the time about the situation on the ground," Miller said at a press briefing. "I'm not going to speak to the specific assessments that led to us to restrict our employees' and family members' personal travel, but clearly we are monitoring the threat environment in the Middle East and specifically in Israel."

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