LANGSA, Indonesia (AP) — A British national working at an oil company was released unharmed Thursday after being abducted by gunmen in Indonesia's Aceh province, police said.

Malcolm Primrose, 61, of Scotland, who is a contract worker for PT Medco E&P Malaka, was found alone at a security post inside a remote palm oil plantation, said East Aceh district police chief Lt. Col. Muhajir, who uses only one name.

Primrose was kidnapped by four gunmen on Tuesday when his car was ambushed. His driver was tied up and left, while Primrose was driven away by the captors.

"We are delighted to confirm that Malcolm Primrose has been released," the British Embassy in Jakarta said in a statement. "Embassy officials are with Mr. Primrose and are providing consular assistance."

Muhajir said the abductors had contacted Primrose's family and requested a $500,000 ransom, but decided to release him after scores of police and troops fanned out to hunt for them. A Medco spokesman, however, said the company was unaware of any demands for money.

Medco said Primrose is a drilling expert who has worked with oil and gas companies in Aceh for more than 30 years.

"With the release of Primrose, we hope that the security situation in East Aceh and our operation area, in particular, will go back to normal for the sake of the investment climate," it said in a statement.

It was not immediately clear who was responsible for the kidnapping. Aceh has a long history of violence, but the government and separatist rebels signed a peace deal in the province in 2005, ending 29 years of fighting that killed an estimated 15,000 people.

Efforts to end the civil war gained momentum after a massive earthquake struck in December 2004, triggering a tsunami in the Indian Ocean that killed 230,000 people, half of them in Aceh.

Under the peace agreement, the rebels gave up their long-held demand for independence and handed over their weapons. The government allowed them to participate in local politics and permitted the predominantly Muslim province to implement a version of Sharia law while enjoying semi-autonomy from the central government.

In 2008, a French World Bank consultant was abducted by suspected former rebels in Aceh but released unharmed 24 hours later.