The USS San Antonio - a U.S. warship docked in Israel's Haifa port.
Carrying 300 Marines and communication equipment, the amphibious vessel docked on Thursday, joining a fleet of warships in the region as the U.S. prepares for possible military strikes on Syria.
U.S. President Barack Obama is awaiting approval from Congress for limited strikes in retaliation for the Syrian government's suspected chemical weapons attack on civilians last month.
Some residents are worried about the heightened U.S. military presence and Israel's involvement in Syria's civil war.
(SOUNDBITE) (English) HAIFA RESIDENT HANNA NASSER, SAYING:
"If the Syrians bomb this warship in the gulf of Haifa and the IDF (Israel Defense Forces) will take part of this war, it will be very bad for all the citizens in Israel."
Others say the threat was nothing new.
(SOUNDBITE) (English) ISRAELI IGOR PATRICK, SAYING:
"All the time (we're) under some - afraid from something, so it's usual for us."
A defense official said the San Antonio could serve as a temporary base for special operations forces if needed.