The U.S. Coast Guard announced Friday it has suspended the search for 11 workers missing after a major oil rig explosion in the Gulf of Mexico.

The Coast Guard's "deepest sympathies and prayers" go out to the families of the missing workers, said Coast Guard Rear Admiral Mary Landry. "We have just made the difficult decision to suspend the search," she said

Earlier Friday, Landry said that conversations with survivors of the blast indicate that the missing workers "might have been in the vicinity of this explosion," which made their chances of survival slim.

"We are working with the families to discuss the suspension of the search at the end of the day today," she said

The Deepwater Horizon rig, located about 42 km southeast of Venice, Louisiana, sank in the Gulf of Mexico Thursday after burning for roughly 36 hours following a major explosion late Tuesday night.

There were 126 people aboard the semi-submerged drilling rig when it exploded. Most of them have escaped safely. Seventeen people were injured.

The explosion left behind an oil slick that oil officials said had the "potential to be a major spill". But the Coast Guard said Friday that there is no oil currently spilling from the sunken oil rig.

Built in 2001, the semi-submersible rig is owned by Houston-based Transocean, the world's largest offshore drilling contractor, and has been under lease by British energy giant BP since 2007.

Officials with Transocean have said that the blast may have been caused by an upsurge in pressure or a blowout from an exploratory well that crews had capped.