Rig contractor Ensco Plc (NYSE: ESV) said Jan. 6 that Petrobras has ended a contract for a drillship over allegations of corruption.

Petrobras chartered the DS-5 in 2008, when it was owned by Pride International, a company Ensco bought in 2011.

Petrobras said in a notice on Jan. 4 that Pride had knowledge that the rig's shipbuilder made "improper payments" to a marketing consultant who then shared the money with former employees of Petrobras, Ensco said.

Ensco said it has found no evidence that Pride, the company or any current or former employees were aware of or involved in any wrongdoing.

The rig contractor said it planned to assert its legal rights under the contract.

Ensco's other rigs leased to Petrobras will continue to work under their contracts, the driller said.

London-based Ensco said it has not been contacted by other Brazil government authorities regarding alleged wrongdoing.