HALIFAX — A Canadian frigate left for Virginia on Wednesday, where it will join a U.S.-led group of ships that will monitor the Persian Gulf for possible terrorist activity.

HMCS Toronto begins the six-month assignment by steaming to Norfolk, Va., to join an aircraft-carrier group, and then carries on to the gulf.

Members of the 235-person crew are expected to monitor boats moving through the gulf, boarding suspicious vessels to carry out inspections.

However, the ship left the port without a Sea King helicopter.

The navy has said the aging aircraft will join the ship in the gulf by March 31, but it will not be able to hoist personnel, refuel in-flight or sling loads.

The helicopter fleet had restrictions placed on it last year after a series of engine problems were reported in other aircraft, prompting an investigation that has yet to determine the cause.

Air crew aboard Toronto have said the restrictions will make the crew's work more difficult but they should be able to perform the bulk of their responsibilities.

The Sea King will conduct surveillance, anti-submarine warfare activities, search and rescue, and provide escort to other vessels as part of the ongoing U.S.-led campaign against terrorism.

The vintage helicopter fleet, which dates back to the mid-1960s, went into what the military called an "operational pause" last Oct. 30, limiting the country's 28 aging helicopters to critical missions only.