Migrants refugees Hungary border Horgos
Migrants teargassed by Hungary riot police at the border with SerbiaMarko Djurica/Reuters

A German company has refused to sell razor wire to Hungary, which is building its border fence with Serbia in a bid to stop asylum-seekers from entering the country, according to reports.

Mutanox, a Berlin-based wholesale supplier of wires and fences, was asked by Hungary in August to submit a tender for the purchase of 9,000 to 10,000 rolls of wire to employ in its infamous fence. But the company refused to go ahead with the sale, citing humanitarian concerns. "The wire is designed to prevent criminal acts," a spokesman for the company told Die Welt. "Children and adults fleeing is not a criminal act."

Hungary purchased the rolls of wire for its four-metre-high and 110-mile-long fences from China, according to reports. Romania has summoned the Hungarian ambassador over the border fence extension to its territory.

Hungary's riot police has used tear gas, water cannons and pepper spray against refugees amassing at the border with Serbia. Several people have received medical treatment from the Serbian ambulance service. Refugees hurled missiles during the clashes, which started after people managed to open a border gate.

Serbia expressed the "harshest possible protest" against Hungary for using tear gas at the border, while Budapest called on its neighbour to act against migrants "attacking police" and said the border would remain closed for 30 days.

UN chief Ban Ki-moon said the treatment of refugees at Serbia-Hungary border was "not acceptable".

Croatia's prime minister, Zoran Milanovic, criticised Hungary's crackdown on asylum seekers, and promised free passage through his country. "We are ready to accept and direct those people," he said, according to AP.

Almost 300 refugees entered Croatian territory after Hungary's decision to seal the frontier.