NEW ORLEANS -- Transocean Ltd. and the Justice Department have discussed a $1.5 billion settlement that would resolve federal civil and criminal claims against the company over its role in the deadly 2010 oil rig explosion.

But Switzerland-based Transocean Ltd. said in a regulatory filing Monday that a "number of issues," including the possible time period for payment, must be resolved before a deal can be completed.

A Justice Department spokesman declined to comment.

Transocean owned the Deepwater Horizon drilling rig, where 11 workers died in an April 2010 explosion triggered by a blowout of BP's Macondo well.

Transocean also says it rejected settlement offers earlier this year from BP and a group of private attorneys for Gulf Coast residents and businesses.