The massive wave of refugees and migrants heading toward Western Europe surged Thursday even as torrential rains played havoc with travelers from Greece to Hungary.

In Hungary, migrants darted across the border from Serbia, sneaking around the unfinished border fence near the village of Roszke. Some were caught and escorted away by police.

The relentless rain came as some 7,000 people streamed across the border from Greece into Macedonia in what Greek police said was the largest group they had seen so far. The surge came after Greek authorities managed to register about 17,000 people on the island of Lesbos.

And more are on the way. The Greek government sent two extra ferries and more registration staff to Lesbos, an Aegean island where more than 20,000 refugees and migrants have been living after arriving from Turkey.

The European Union is seeking backing for plans to distribute 200,000 people among its members, but it is meeting fierce resistance from some member nations.