A Maritime Self-Defense Force destroyer and refueling ship left port Monday as part of Japan's logistic support for the U.S.-led war on terrorism in and around Afghanistan.

The 4,550-ton destroyer Harusame and the 8,150-ton refueling ship Tokiwa will relieve two other MSDF ships in the Indian Ocean when they arrive on station in mid-December, the Maritime Staff Office said.

The two ships currently engaged in the refueling operation are the destroyer Samidare and refueling ship Towada, which sailed out of Kure, Hiroshima Prefecture, last summer, the office said.

Critics say the support mission in the Indian Ocean and elsewhere will constitute indirect support for an attack on Iraq long threatened by the United States.

The two ships that left Monday have a combined crew of about 350. They bring to 19 the number of ships that have been deployed since Japan passed legislation on antiterrorism measures in October 2001.

After the special law was enacted, Japan compiled a six-month basic plan for measures to provide logistic support to the U.S.-led campaign in Afghanistan. It was extended for six months in May and again when it expired last week.

Under the current support plan, MSDF ships supply oil to U.S. and British vessels in the Arabian Sea.