US Coast Guard crews searched for five crewmembers missing after their offshore supply vessel collided with a container ship and sank near the mouth of the Mississippi River in southeastern Louisiana.

Coast Guard Petty Officer Jonathan McCool said rescuers found life rings and a lifeboat from the 178-foot Lee III, but no sign of the crew. The downriver-bound Lee III and upriver-bound 534-foot Zim Mexico III collided at about 5:20 a.m. CST (6:20 EST), McCool said. ?The cause of the accident is under investigation,? he added.

The collision caused the Coast Guard to close all shipping traffic at a location called the Southwest Pass, the main entrance for deep-draft vessels into the Mississippi from the Gulf of Mexico, McCool said.

The Zim Mexico III, which reported minor damage and no injuries, is owned by B. Rickmers GMBH Cie. and operated by Zim American Israeli Shipping Co., McCool said. The Lee III is owned by Ocean Runner Inc. in Galveston, Texas, he said.