Guyana’s government has formally protested to Venezuela following the completion by Venezuela’s armed forces of a bridge built on a remote river island shared by both countries.

GEORGETOWN, Guyana (AP) — Guyana’s government Saturday formally protested to Venezuela following the completion by Venezuela’s armed forces of a bridge built on a remote river island shared by both countries. Work on the bridge, which links Venezuela’s mainland to a military base, has caused a decades-old row over border lines in the Essequibo region to flare up again.

Guyana Foreign Minister Hugh Todd said in a statement that he was forced to summon Venezuelan Ambassador Amador Perez Silva to his office Thursday to condemn the move by Venezuela to build the bridge.

The bridge links Venezuela’s mainland to the eastern side of Ankoko island. The ministry claims the bridge connects the Venezuelan mainland to a small military base that Venezuela built illegally on Guyana’s side of Ankoko, a small island that is mostly inhabited by gold miners and military personnel.

The two neighboring states have feuded over land and maritime borders for decades as Venezuela claims that an 1890s boundaries commission cheated it out of the oil rich Essequibo region. The region currently makes up two-thirds of Guyana’s territory. The area was administered by Britain for more than a century, and it has been under Guyanese control since 1966, when the nation gained its independence from the United Kingdom.