After accusing Belarusian authorities of flying in refugees from overseas to send illegally into the European Union, Lithuania began constructing a barrier along its border with Belarus on Friday.

The initial barrier will be 500 meters (1,640 feet) long, 1.8 meters (six feet) high, and made up of concertina and razor wire, according to Ruta Montvile, spokesperson for the army’s defense chief.

Belarus voted in May to allow migrants into EU Member Lithuania in response for EU sanctions imposed after Minsk forced a Ryanair flight to land on its grounds and detained a dissident blogger on board.

“If anyone believes we will close our border with Poland, Lithuania, Latvia, and Ukraine and turn into a detention center for those fleeing Afghanistan, Iran, Iraq, Libya, Syria, Tunisia, and further down Africa – if anyone believes that, he is misguided, to put it mildly,” Belarus President Alexander Lukashenko said on Tuesday.

Belarus is now simply protecting the border to the extent that it is “profitable” and financially feasible, according to the president.

“If someone wants more, we’re ready to sit down at the table and negotiate on the terms under which we’ll do it,” he continued.

Lithuania announced on Wednesday it would put up the frontier barrier and deploy troops to prevent migrants crossing illegally into its territory. The 679 km (420 mile) border Lithuanian-Belarus border runs over sparsely populated areas, with large stretches going through forests and marches.

Just over 1,500 people crossed the frontier this year, with 900 of them coming over the first nine days of July.

Lithuanian Prime Minister Ingrida Simonyte told national broadcaster on Friday she didn’t expect the migrant flow from Belarus to subside on its own.

“Given that the Belarus regime makes money from these people through visa fees and, I believe, other sources of income as well,” she said, “it would be difficult to expect any positive trend without other ways of effect.”

According to the Interior Ministry, around 78 km (48 miles) of the border was fortified in previous years, and about 258 km (160 miles) is monitored electronically.

According to Simonyte, Belarus was offering migrants flights to Minsk on Wednesday, using documents found on at least one migrant who had arrived in Lithuania.

Baghdad was the major airport from which people flew into Belarus, she added, adding that people were also flying in from Turkey.