Polish contractors have begun work on a $407-million (€353-million) wall along the Belarus border aimed at deterring migrant crossings following a crisis in the area last year.

The 5.5-metre high wall will run along 186 kilometres of the border – almost half the total length – and is to be completed in June, according to Krystyna Jakimik-Jarosz, a border guard spokeswoman.

“As planned, the construction sites were turned over to the contractors on Tuesday,” said Jakimik-Jarosz.

She refused to reveal the exact locations “for security reasons” but said the wall would be equipped with cameras and motion detectors.

Previously, Poland also built a razor wire fence along much of the border and closed off the frontier area to media and human rights groups.

Jakimik-Jarosz said the razor wire fence had helped the border guards.

“It bought us time to prepare when a group of migrants were getting ready to attack, to create an opening. We had the time to mobilise the means and personnel required to stop them,” she said.

Poland has also approved a new law allowing migrants to be forced back into Belarus.