Burundi police have stopped all private buses from crossing the border into Rwanda, as tensions between the neighbours remain high.

Buses belonging to transport companies including Yahoo Car, Volcano and Horizon left the capital Bujumbura on Thursday morning, but were stopped for several hours by police at the border.

The passengers, mostly from Burundi and Rwanda, had to disembark and walk across the border with their luggage to take other buses on the Rwanda side of the border, said a spokesperson for Yahoo Car.

“Some of our buses were obliged to go back to Bujumbura,” he added. Others were still at the border.

The National Police Spokesman Pierre Nkurikiye told reporters later in the evening that buses were prevented from crossing the border as part of the Burundi government measure forbidding exports of Burundian food crops to neighbouring countries. The food export ban came into effect a week ago.

“Those companies had repeatedly violated the measure by transporting food across Rwanda from Burundi,” said Nkurikiye.

However, Nkurikiye did not exclude the possibility of security reasons being behind the decision. He also acknowledged that the ban applied only to transport crossing into Rwanda.

“The armed groups which destabilise Burundi come from Rwanda by those companies,” claimed Nkurikiye.

The Burundi government has been claiming since last year that the Rwandan government is providing support to Burundians trying to topple President Pierre Nkurunziza’s government.

Burundi has been plagued by instability and low-level violence since Nkurunziza announced in April 2015 that he was running for a third term as president despite the two-term limit set out in the constitution.

A week ago, Burundi’s second vice president Joseph Butore visited Cibitoke province, bordering Rwanda, where he instructed police and customs officials to stop the exports of Burundian food to Rwanda.

“We cannot sell to Rwanda what we produce ourselves because that country wants to fight against us,” he said.