1.   Because the tugs push and pull engineless barges carrying cargo, their crews must be entirely American.

2.   The tugs push or pull barges carrying oil, grain, scrap metal or trash, and help clumsy passenger ships steer through the slender waters.

3.   The gunmen stopped the tugboat, which was pulling a barge, fired warning shots and abducted the captain and three officers, navy officials said.

4.   The gunmen stopped the tugboat, which was pulling a barge, fired warning shots and abducted the captain, Joel and two other officers, navy officials said.