Macedonian authorities have briefly opened their border with Greece to refugees heading for central Europe, allowing in a few score. About 10,000 people remain camped at the crossing, awaiting their turn.

Greek police say Macedonia opened the crossing from midnight Tuesday to 2 a.m. Wednesday, and from 7 a.m. to 9 a.m. Wednesday, admitting 170 people from Syria and Iraq.

Hundreds, including many families with small children, arrive daily at the Idomeni crossing in northern Greece, where two official camps are so full that thousands have set up tents in fields all around.

Macedonia says it will only allow in as many refugees as Serbia, its northern neighbor, takes each day. The tiny trickle has caused a huge backlog in Greece, where most refugees and other migrants reach Europe.