Bomb threats close Boston Harbor

Boston Harbor

BOSTON (CNN) -- The Boston Harbor was shut down Sunday for about three hours after the U.S. Coast Guard received two bomb threats.

After a sweep of the area, Coast Guard officials found no sign of anything suspicious and reopened most of the harbor.

One reserve channel, an area where vessels move in and out of the harbor, remained closed Sunday morning, Coast Guard Petty Officer Zach Zubricki said.

"While the harbor was closed, any vessel in the area was asked to stand by," Zubricki said.

A booking agent for Norwegian Cruise Lines said passengers aboard a cruise ship scheduled to dock at 7 a.m. EDT were still on the ship at 9 a.m.

"They're still on the ship because they don't know where to dock the boat," said agent Bailey Chung.

The Norwegian Majesty was returning to Boston from a cruise in St. George, Bermuda.

The shutdown occurred at 5:15 a.m. EDT. Vessels were allowed back into the harbor through other channels around 8:15 a.m. EDT.

Security around the country is on high alert in the wake of Tuesday's terror assault. The Coast Guard has begun patrolling parts of the East Coast.

Two of the jets hijacked in Tuesday's attacks originated from Boston's Logan Airport.