Hungary has started building a new fence on its southern border with Serbia as part of its efforts to keep migrants and refugees from freely entering the country.

Two kinds of barriers are being tested before construction begins in earnest.

The government said the new fence which will have electronic surveillance equipment, was needed in case of a new surge of people moving towards Western Europe.

Last year, Hungary built fences protected with razor wire along some 175 kilometers of its border with Serbia and shorter sections on the border with Croatia.

Before the border was sealed in mid-October, nearly 400,000 people passed through the country on their way to Germany and other destinations.