“There are currently 770 Serbian citizens in Sweden, most of whom are Roma, who are requesting political asylum,” Swedish ambassador in Belgrade Krister Bringeus was quoted as saying in the Danas daily.

“All 770 people came to Sweden in last two months, which is equal to the number of people that came to the country during the whole of last year. We are very concerned over the situation,” Bringeus said.

“None of them will be granted asylum and all will be sent back home in the coming days under an emergency procedure,” he added.

Sweden is the second EU state after Belgium to have raised an alarm over an influx of asylum seekers since the European Union lifted visa restrictions for citizens of Serbia, Montenegro and Macedonia in December.

They are now allowed to travel freely into the Schengen zone which covers a majority of EU countries.

According to figures from Belgium, 58 ethnic Albanians sought asylum there in January and the number swelled to 330 in February.

Serbia has said it would take back all those who sought asylum in accordance with agreements on readmission it signed with EU member states.

Interior Minister Ivica Dacic said Serbia would open a probe into the case, as the asylum seekers had been organised. According to local media reports travel agents set up bus tours to EU countries luring locals with stories that they would get political asylum, a job and a house there.

Macedonia and Serbia have agreed to investigate the possibility of prosecuting the organisers of the bus lines, Dacic told the Beta news agency.

The first bus carrying failed Serbian and Macedonian asylum seekers back from Belgium was expected to arrive in the towns of Presevo and Kumanovo respectively later.

The bus is carrying more than 40 people who have all agreed to withdraw their asylum requests and return home voluntarily.