Latvian authorities have discovered an underground tunnel through which migrants could enter the EU country from neighbouring Belarus, Interior Minister Jānis Dombrava reported in Riga on Tuesday.

Dombrava said the secret passage was discovered by border guards, the military and police near the closed Silene border crossing.

“It is the first tunnel of this kind in Latvia,” Dombrava said, according to Latvian media reports. He ordered a search for additional underground passages using electronic equipment. In recent weeks, secret tunnels under the border between Belarus and Lithuania had already been discovered.

The tunnel, located about 10 metres from the border fence, was discovered while authorities were trying to reconstruct the route taken by a group of migrants who had been detained after illegally crossing the border. According to the Latvian border guard service, 15 people were arrested.

Until now, migrants had only attempted to enter the EU country by scaling the border fence. According to a border guard spokesman, they had used various tools for this, including metal cutters and makeshift ladders made from branches and sticks.

Latvia, like Lithuania and Poland, has repeatedly accused authoritarian-ruled Belarus of deliberately and systematically bringing migrants from crisis regions to the EU’s external border. In response, Latvia strengthened border security and built a border fence.

The country, which is also a NATO member, has launched a new operation to secure its eastern border under which drones will be deployed more extensively to detect illegal crossings.