The US Coast Guard has suspended a search for 11 workers missing after an oil rig exploded and sank into the Gulf of Mexico earlier this week.

The 11 workers - who were likely on the deck of the oil rig in the vicinity of the explosion - are presumed dead, the Coast Guard said.

The Transocean Ltd Deepwater Horizon sank after burning for two days. Workers had been attempting to cap a new well on the rig south-east of Venice port in Louisiana.

Some 115 of the 126 workers who were on board at the time of the explosion were rescued.

A remotely operated unmanned submarine sent down to inspect the scene found no oil leaking from the rig and no oil flowing from the well, reducing the risk a major spill, a spokeswoman said.

"As of right now, the spill is not growing," a U.S. Coast Guard spokeswoman said.