RIO DE JANEIRO, Aug. 15 (Xinhua) -- A Brazilian navy troop seized a motorboat full of weapons on Thursday in Guaruja area, in the southeastern Sao Paulo state, official sources said on Friday.

　　The motorboat, which belonged to a group of pirates, was seized with three 12-millimeter carbines, a nine-millimeter submachine gun, a 40-millimeter pistol and some ammunition on board, said the commandant of Sao Paulo state's Port Authority, Afranio de Paiva Moreira Junior.

　　The pirates were robbing ships when they encountered a navy patrol. The five men on the boat jumped into the sea and swam to the shore to escape, said Moreira Junior.

　　"The weapons are similar to those described by victims of recent robberies in this area," he said.

　　The Port Authority called the Federal Police to help investigate the case.

　　Four boats were reportedly robbed in the Santos Bay, southeast of Sao Paulo, in February and March this year.