Somali pirates captured four ships and took more than 60 crew members hostage in a brazen hijacking spree, while the American captain freed from their grip planned to reunite with his crew and fly home Wednesday to the United States. Pirates have vowed revenge for the deaths of three colleagues at the hands of U.S. snipers rescuing Capt. Richard Phillips, as well as for two others slain by French forces in a separate rescue last week. "Our latest hijackings were meant to show that no one can deter us from protecting our waters from the enemy because we believe in dying for our land," Omar Dahir Idle, a pirate based in the coastal town of Harardhere, told The Associated Press by telephone. "The recent American operation, French navy attack on our colleagues or any other operation mean nothing to us." The top U.S. military officer said on Tuesday he takes such comments seriously. But Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, told ABC's "Good Morning America" that "we're very well prepared to deal with anything like that." Capt. Phillips, who offered himself up as a hostage to save the crew of the Maersk Alabama, was rescued Sunday when U.S. Navy SEALs shot three pirates dead after a five-day standoff.