Thousands of migrants have crossed unhindered from Greece into Macedonia after overwhelmed security forces appeared to abandon their efforts to stem the flow through the Balkans to Western Europe after days of chaos and confrontation.
Riot police remained posted on Macedonia's border with Greece on August 23, but did little to slow the passage of thousands of migrants who have been stranded at the border, many of them refugees from the Syrian war and other conflicts in the Middle East.
Macedonia declared a state of emergency on August 19 and sealed its southern border to migrants who had been pouring across at a rate of 2,000 per day on their way to Serbia, then Hungary and the European Union's visa-free Schengen zone.
Macedonian riot police on August 22 used tear gas and stun grenades to drive back crowds, but were overwhelmed by several thousand who tore through police lines or ran through nearby empty fields.
WATCH: Migrants Stream Into Macedonia (RFE/RL's Balkan Service, natural sound)
Serbian Defense Minister Bratislav Gasic, visiting a migrant reception center on Serbia's southern border with Macedonia, said more than 5,000 people had entered overnight as Macedonia cleared the backlog.
"We expect the wave in the next day or two to be of a similar intensity," Gasic was quoted as saying on August 23 by the Serbian state news agency, Tanjug.
He added: "Police are working in three shifts, papers are being issued around the clock."
Macedonia is a major transit country for people leaving Syria, Afghanistan, Northern Africa, and elsewhere with the goal of reaching western and northern EU countries.
Amet Alimi, president of Presevo's Red Cross branch, told the AFP news agency: "We have worked all night to admit them. There is a flow of people who keep coming."
In related news, more than 4,000 migrants have been rescued over the past 24 hours in the central Mediterranean off the Libyan coast, according to the Italian Coast Guard.
The migrants were travelling aboard inflatable dinghies and overcrowded boats, the Coast Guard said on August 23.
No casualties were reported in the rescue operations that involved various Italian vessels and also Norwegian and Irish ships.
More than 2,000 people have died this year in attempts to reach Europe in overcrowded, boats, according to the International Organization for Migration.
Europe is struggling with a huge influx of migrants, including many children, in what the EU has called its worst refugee crisis since World War II.