Hungarian troops overnight began laying a razor-wire barrier along its border with Croatia to keep migrants out, Prime Minister Viktor Orban said Friday, following a similar move along the frontier with Serbia.
"During the night work already began on building the technical border closure... It seems we can rely on help from no-one," Orban said in an interview on public radio after thousands of migrants entered Croatia seeking to travel to northern Europe.
"Forces are being redeployed, 600 soldiers are already at the scene, 500 will arrive there in the course of the day, at the weekend another 700. Two hundred police are there already, another 100 will go down today and another 500 at the weekend," he said.
"There will be no sandhill or molehill to hide behind, we will defend our borders."
He said that the barrier was being put in place along 41 kilometers (25.5 miles) of the 330-kilometer border. Along the rest flows the difficult-to-cross Drava river.
Hungary this week sealed its border with Serbia, cutting off a major entry point into the European Union for tens of thousands of migrants from the Middle East, Asia and Africa traveling up through the western Balkans.
This has diverted some 13,000 migrants from Serbia into Croatia, overwhelming local authorities and forcing Zagreb to close most of its border on Thursday.
Local media reported small groups of migrants crossing into Hungary from Croatia on Thursday.
Police said Friday that 453 illegal immigrants were detained in Baranya county -- next to the Croatian border -- by midnight (2200 GMT), mostly Syrians and Afghans.
Hungary meanwhile declared a "state of crisis" in two counties near the Croatian border and in two others near the Slovenian and Austrian borders.
A similar state -- paving the way for the large-scale deployment of the army and police in border control, pending parliamentary approval -- is already in force in two other counties along the Serbian border.
"The western Balkans route is still there. The fact the Hungarian-Serbian border is now closed has not stopped the flow," Orban said.
The right-wing Orban has come under heavy criticism for Hungary's treatment of the migrants, particularly over the police's handling of clashes at the flashpoint Serbian border crossing of Roszke on Wednesday, and for reinforcing its borders.
But Orban, while warning against the dangers of Europe letting in so many Muslims, says he is applying EU regulations and blames Greece for waiving the migrants through and Germany for relaxing asylum rules for Syrians.
In addition to laying razor wire all along the border with Serbia, Hungary is also building a fence four meters high and also intends to reinforce its border with Romania.
This week tough new laws took effect giving courts the power to jail people for up to three years for crossing the border "illegally," rising to five years if they damage the barrier.