Three Dutch navy personnel were captured by Libyan forces loyal to embattled ruler Colonel Muammar al-Gaddafi on Sunday while trying to extract two European nationals from the North African country. The Netherlands’ Defense Ministry reported the incident on Thursday and said that “intensive diplomatic negotiations” were underway with Libyan authorities about the release of their men.

The crew were trying to evacuate a Dutch and European Union citizen from the city of Sirte, centered halfway between Tripoli and Benghazi on the Mediterranean coast. They deployed in a Lynx helicopter from the HNLMS Tromp which is anchored off the Libyan coast.

The Tromp, which was commissioned in 2003 and had been participating in anti-piracy operations off the Horn of Africa until last month, was underway to make port in February when anti-government protests erupted in Libya. The frigate was deployed to the Gulf of Sidra to potentially assist in the safe return of Dutch nationals.

Since civil unrest rocked Libya three weeks ago, rebel forces have claimed control of major cities in the eastern part of the country. Libya’s longtime ruler Colonel Gaddafi was able to cling to power by deploying heavy military force against demonstrators but his realm of control seemed limited to the capital of Tripoli by the time the Dutch mounted their rescue effort.

Libyan state television aired footage of the Dutch helicopter and members of its crew along with weapons they carried, noting that they did not have permission to enter Libyan airspace.

The Dutch Defense Ministry would not describe the captured aviators as “hostages.” Libya and the Netherlands are not in a state of war.

Prime Minister Mark Rutte said that news of the men’s capture had been kept quiet for several days to advance talks on their release. “Everything is being done to make sure the crew gets home,” he said.

With fellow EU member states, the Netherlands have enacted sanctions against the Gaddafi regime, including a weapons embargo and the freezing of financial assets abroad. The International Criminal Court, which is seated in The Hague, has warned Gaddafi and members of his family that they could face war crime charges if the state violence against protesters continues.

The two European nationals the Dutch crew was trying to extract from Libya were released by authorities and able to flee the country.