Mladić's arrest was announced by Serbian President Boris Tadić at a hastily convened press event, just as High Representative Catherine Ashton was en route to Belgrade for a visit during which she had been expected to warn Serbia that the arrests of war criminals Ratko Mladić and Goran Hadžić were a sine qua non precondition of the country's accession to the EU.
"On behalf of the Republic of Serbia I can announce the arrest of Ratko Mladić. The extradition process is under way," Tadić announced, adding: "This removes a heavy burden from Serbia and closes a page of our unfortunate history."
Mladić was arrested in the village of Lazarevo, near the northeastern town of Zrenjanin, around 100 km (60 miles) from the capital Belgrade and close to the Romanian border, a police official said.
Reportedly, the house in which he was hiding was owned by a relative of Mladić and had been under surveillance for the last two weeks.
As commander of the Bosnian Serb forces in the 1992-95 Bosnia war, Mladić was indicted by an international war crime court in 1995 for the massacre of 8,000 Muslim men and boys in the town of Srebrenica and a brutal 43-month siege of Sarajevo (see 'Background').
"This is an important step forward for Serbia and for international justice," EU foreign policy chief Catherine Ashton said in a statement.
"We expect Ratko Mladić to be transferred to the International Criminal Tribunal for the former Yugoslavia without delay. Full cooperation with the ICTY remains essential on Serbia's path towards EU membership," she added.
Enlargement Commissioner Štefan Füle today called an extraordinary press conference, stressing that the Serb authorities had delivered and proved their credibility.
Indeed, according to many reports, Western governments had doubted whether Belgrade was genuinely determined to arrest Mladić, who is seen by many of his compatriots as a hero.
He paid special tribute to Tadić, not only for helping to bring Mladić before the Hague tribunal, but also for his role in fostering reconciliation and regional stability.
Füle expressed hope that Serbia would obtain EU candidate status before the end of the year. Of the countries currently on the road to accession, Croatia, Macedonia, Turkey, Iceland and Montenegro have obtained candidate status, while Serbia, Bosnia and Herzegovina, Albania and Kosovo are categorised as "potential candidates".
Netherlands still cautious
Asked by EurActiv to comment on the position of the Netherlands, whose prime minister apparently caution over the arrest, Füle said: "Is Serbia closer today to the European Union than it was yesterday? Yes! The answer is absolutely yes. Does it remove the list of the reforms, the list of the benchmarks that are still to be fulfilled, before the Commission is able to make the respective recommendation? No. The list is just shorter by one point."
Dutch Prime Minister Mark Rutte was quoted by Reuters as saying that the arrest of Mladic was an important precondition pf Serbia's entry to the EU, but did not mean automatic accession.
The arrest of Mladic mirrors that of Radovan Karadzic two years ago, which took place ahead of important EU decision-making regarding Serbia's EU accession path. Asked to comment on this, Füle declined to add to speculation.
The Netherlands has a special interest in Serbian war criminals. In 2002, the government of Wim Kok accepted partial responsibility and resigned for having mishandled the situation in Srebrenica (see 'Background').
But perhaps more importantly, under pressure from populists, the Dutch government seems to be the EU's most sceptical with regard to future EU enlargement.
Many EU leaders used Twitter as a communication tool to express their feelings as the news broke.
European Commission President José Manuel Barroso, who is participating in the G8 summit at Deauville, tweeted: "Mladic arrest shows Serbia keeping word so we should trust determination to come closer to EU".
In a series of tweets, Swedish Foreign Minister Carl Bildt, who was a high-profile mediator during the Yugoslav wars, expressed his satisfaction and expressed hopes for Serbia's future.
"I have very warmly congratulated President Tadic on the arrest of Mladic. I never doubted his determination and know how hard he worked on this […] A dark chapter in European history can now be closed! And we can look at much brighter EU prospects for all of the Western Balkans," he wrote.
Bildt also indicated his willingness to serve as a witness at Mladic's trial. "Look forward to returning to the Hague and ICTY to give the help I can give in the Mladic trial," he tweeted.
NATO Secretary-General Anders Fogh Rasmussen tweeted: "I strongly welcome the news that Ratko Mladic has been arrested and that his extradition to the Hague is under way […] Almost sixteen years since his indictment for genocide and other war crimes, his arrest finally offers a chance for justice to be done."