SAN DIEGO -- The USS Nimitz and several other American warships left San Diego Monday for the Persian Gulf to join another locally based aircraft carrier strike group already in the region.

The nuclear-powered aircraft carrier will join the San Diego-based John C. Stennis Strike Group and relieve the USS Dwight D. Eisenhower, according to Naval Air Forces Public Affairs.

Military officials said in a statement that the two-carrier presence in the Persian Gulf area is intended to demonstrate U.S. "resolve to build regional security and bring long-term stability to the region."

The Nimitz's departure comes amid heightened tensions in the region following the detention of 15 British sailors and marines by Iran. Iran maintains the detainees were operating in its territorial waters, a charge the British government denies.

President Bush ratcheted up the rhetoric over the weekend, calling the detainees "hostages" -- a term not even the British had used.

The tension over the detainees coincides with international pressure on Iran to give up its uranium enrichment program, which it maintains is strictly for peaceful purposes. The United States and other nations fear Iran is working toward the development of nuclear weapons.

The Nimitz will support the war on terrorism, patrol the Horn of Africa and conduct marine security operations as part of the larger effort to "deter and dissuade others from acting counter to U.S. national interests," according to a Navy statement.

Accompanied by his family at Naval Air Station North Island Monday morning, a sailor preparing for his fifth deployment said the departures aren't getting any easier for his three young daughters -- a 22-month-old, a 3-year-old and a 5-year-old.

"It seems to be getting a bit harder because they're all older and they seem to know that something's going on ... Daddy's not going to be around," he said.

"You just tell them every night, you know, Daddy's trying to keep us safe," the sailor's wife said, adding the family corresponds overseas via e-mail and video teleconference.

The Nimitz Strike Group comprises the guided-missile cruiser Princeton, guided-missile destroyers Higgins, Chafee, John Paul Jones and Pinckney, two helicopter squadrons and an explosive ordnance disposal unit.

The Stennis and its strike group left Naval Base Coronado on Jan. 20. It is the largest carrier presence in the Persian Gulf since the start of the war in Iraq.