A Briton and a New Zealander were found dead in western Libya this afternoon, while two Americans were arrested in the eastern city of Benghazi, Libyan security sources said.

The security situation has deteriorated in recent months in the North African country where the government is struggling to rein in militias and tribesmen who helped oust Muammar Gaddafi in 2011 and kept their guns.

"Their bodies were found near the coastal area of Mellitah," one source said, referring to a large oil and gas complex co-owned by Italy's ENI and a residential area near the town of Zuwarah and 100 km (60 miles) west of Tripoli.

Another source said the New Zealander was a woman and the Briton a man. Both were found outside the oil complex, he said. They had gunshot wounds.

No further details were immediately available.

In a separate incident, two Americans were being held by the Libyan army at its headquarters in the eastern city of Benghazi, several security and army sources told Reuters.

Both were basketball players and were arrested on the campus of Benghazi University, one security source said.

"They were arrested by university guards and then brought by special forces to the army barracks," an army source said.

The State Department and Britain's Foreign Office both said they were looking into the matter.

Last Friday, four American military personnel were detained by the Libyan government and released after several hours in custody, U.S. and Libyan officials said.