LAGOS, Nigeria (AP) — Sierra Leone’s government on Tuesday said that several members of a security team, including an officer, were apprehended and transported over the border by members of Guinea’s military.

For more than two decades, the West African countries have been involved in a border dispute that stemmed from the Sierra Leonean civil war between 1991 and 2002. Sierra Leone’s government had invited Guinea to help defend its eastern borders during the war, but the Guinean troops didn’t completely withdraw after the war.

Last year, the Guinean military entered a mineral-rich border town in Sierra Leone, sparking regional concerns.

The latest incident, according to a statement by the Sierra Leonean government, happened on Monday at the border town of Kalieyereh in Falaba district, where it said members of its armed forces and police were working on “making bricks for the construction of a border post and accommodation facility” for the border post.

The weapons and ammunition of the apprehended members of the security team were also taken, the government said. The statement didn’t provide an exact number of how many people were taken into Guinea.

The “government is actively engaging through established diplomatic and security channels to confirm their location and secure their safe and unconditional release,” the statement said.

Guinean authorities didn’t immediately comment on the incident.

Sierra Leone said its national flag was hoisted in the town in which the incident on Monday incident, and the territory is recognized as belonging to Sierra Leone.