The number of migrants entering Hungary from Serbia has hit a new record amid tension in eastern Europe over how to deal with the crisis, the media reported on Sunday.
Over 4,000 people walked across the border with Serbia on Saturday just as the authorities in Hungary were completing preparations to seal the frontier, BBC reported.
They were taken to a field where dozens of large tents, including those of the UN refugee agency, now stand.
Officials have estimated that 175,000 migrants have crossed from Serbia into Hungary so far this year.
However, Hungarian Prime Minister Viktor Orban has pledged to seal the country's borders and arrest any illegal migrants. The country is close to finishing a 4 metre-high fence along the border with Serbia.
More than 4,000 Hungarian soldiers have been brought in to help police enforce a ban which Orban has ordered must come into effect on Tuesday.