TOKYO — Two Japanese navy destroyers left today to join an international anti-piracy mission off the coast of Somalia, despite concerns troops could be pressed into combat in violation of the country's pacifist constitution.

The five-month deployment marks the first overseas policing action for Japan's military, which is limited by the country's post-World War II charter to defensive missions. The military's forays abroad have been largely restricted to refueling, airlifting and other humanitarian activities.

The two Japanese destroyers, Sazanami and Samidare, which are also carrying two patrol helicopters and a pair of speedboats, are expected to reach Somali waters in early April. Together they carry about 400 sailors, including specially trained commandos.

Authorities say marauding criminals in speedboats attacked more than 100 ships off Somalia's coast last year, including high-profile hijackings with multimillion-dollar ransom demands.

By The Associated Press