The Hungarian government placed a full-page advertisement in a leading Lebanese newspaper on Monday, warning migrants that they can be jailed if they enter the country illegally.

The “strongest possible action is taken against those who attempt to enter Hungary illegally,” the piece in the An-Nahar said. At least 2.1 million Syrians have been registered by the UN Refugee Agency in Lebanon, Egypt, Iraq and Jordan, while 1.9 million have been registered in Turkey.

Speaking in parliament Monday, Hungarian Prime Minister Viktor Orban said millions of migrants are “laying siege” to the borders.

He said “the migrants are not just banging on our door, they are breaking it down” and insisted that razor-wire fences the country is building on its borders with Serbia, Croatia and Romania are needed to defend Hungary and Europe, the Associated Press reported.

Hungary closed its border with Serbia on Sept. 15 and reopened it Sunday for vehicles, which will be checked by authorities.

In Turkey overnight, about 700 mainly Syrians who waited at Istanbul’s main bus station for a week after authorities suspended ticket sales to the northwestern town of Edirne, set out to walk the 150 mile distance to the town, near the Greek border, in an effort to reach Europe, Agence France-Presse reported.

Some managed to board buses and private vehicles en route, but those who failed to do so were blocked by police about 31 miles from Istanbul, according to the news agency.

In Greece, fewer boats than normal landed on the island of Lesbos — a major transit point for Syrian refugees heading to Europe from Turkey — on Monday morning, ahead of an expected thunderstorm, Reuters reported.

It came after 13 migrants died when their boat collided with a ferry off Turkey on Sunday.

Hundreds of thousands of migrants and refugees, many of them from Syria, Afghanistan, Iraq and Eritrea, have headed to Europe this year fleeing conflict at home as countries along the route struggle to cope.

Monday, Austrian police spokesman Helmut Marban said nearly 24,000 refugees entered the country during the weekend, and another 3,200 arrived at the Nickelsdorf crossing — the main border crossing from Hungary — on Monday morning. Greek police also said 8,500 asylum-seekers crossed into neighboring Macedonia in the last 24 hours, the AP reported.

Foreign ministers from Hungary, Poland, Slovakia and the Czech Republic are due to meet Monday, when they are expected to voice opposition to Germany’s call for a more even distribution of migrants, the BBC reported. Germany says it is expecting at least 800,000 migrants this year.

European Union interior ministers are due to discuss the crisis the following day and on Wednesday, EU leaders will gather for an extraordinary meeting in Brussels on how to deal with the influx of migrants and refugees.

Secretary of State John Kerry on Sunday said that the U.S. will accept 85,000 refugees from around the world next year, up from the previous quota of 70,000. He also said the total would rise to 100,000 in 2017.

USA TODAY reporter Kim Hjelmgaard is currently traveling the land route taken by many migrants from Lesbos, Greece, to Berlin, Germany. Follow his journey here: