(CNN) -- World leaders and human rights groups celebrated the arrest of former Serbian army commander Ratko Mladic on Thursday, calling it "historic" and "an important step forward."
It is "an important day for international justice," said the office of Serge Brammertz, prosecutor of the International Criminal Tribunal for the Former Yugoslavia, in a written statement.
"Mladic's arrest clearly signals that the commitment to international criminal justice is entrenched. Today's events show that people responsible for grave violations of international humanitarian law can no longer count on impunity."
The office awaits Mladic's transfer to The Hague, where he will stand trial, the statement said.
Mladic is charged with crimes including the murders of nearly 8,000 Bosnian Muslim men and boys in Srebrenica in 1995; forcible transfers and detentions of Bosnian Muslims and Croats; a "terror campaign and the shelling and sniping of civilians in Sarajevo by Bosnian Serb forces under his command"; and the taking of United Nations military observers as hostages, the statement said.
"With the news of the arrest," Brammertz said, "we think first and foremost of the victims of the crimes committed during the conflicts in the former Yugoslavia. These victims have endured unimaginable horrors -- including the genocide in Srebrenica -- and redress for their suffering is long overdue."
U.N. Secretary-General Ban Ki-moon called it a "historic day for international justice. This arrest marks an important step in our collective fight against impunity as well as for the work of the" tribunal.
He praised Serbian President Boris Tadic and the Serbian government.
U.N. High Commissioner for Human Rights Navi Pillay said Thursday that she hopes "Mladic's trial, along with that of Radovan Karadzic, and the recent ICTY convictions of Ante Gotovina and Mladen Markac, as well as the dozens of earlier convictions, will help victims and their families see justice done and receive acknowledgement of their suffering."
Former Serbian leader Karadzic -- who was arrested in Belgrade, Serbia, in 2008 -- faces 11 counts of genocide, war crimes and crimes against humanity. He has denied the charges.
Gotovina commanded Croatia's Split military district during the mid-1990s war, while Markac headed Croatia's Interior Ministry's Special Police.
Both were convicted of war crimes and crimes against humanity.
NATO Secretary General Anders Fogh Rasmussen said he strongly welcomed the news. "As Bosnian Serb military commander, General Mladic played a key role in some of the darkest episodes of Balkan and European history, including the siege of Sarajevo and the massacre of thousands of Bosnian men and boys in Srebrenica in 1995. Almost 16 years since his indictment for genocide and other war crimes, his arrest finally offers a chance for justice to be done."
The White House issued a statement Thursday applauding Tadic and the government of Serbia on "their determined efforts to ensure that Mladic was found and that he faces justice."
"We look forward to his expeditious transfer to The Hague," the statement said. "Today is an important day for the families of Mladic's many victims, for Serbia, for Bosnia, for the United States, and for international justice.
"May the families of Mladic's victims find some solace in today's arrest, and may this deepen the ties among the people of the region," it added.
French President Nicolas Sarkozy welcomed the news while hosting the G8 summit in Deauville, France, calling the arrest "very big news."
"It is a very brave decision by the Serbian president, and it's an important step towards the integration in the near future (of Serbia) into the European Union," he said.
European Union foreign policy chief Catherine Ashton called the arrest "an important step forward for Serbia and for international justice." It is "a very positive development for the European Union, for Serbia's neighbours, but most of all for the rule of law in Serbia itself," she said. "The families of his countless victims deserve justice."
British Foreign Secretary William Hague said the arrest "is a historic moment for a region that was torn apart by the appalling wars of the 1990s."
He added, "Our sympathies are with all those who lost loved ones during those conflicts. Today should mark the beginning of a new chapter for the countries of Western Balkans."
British Prime Minister David Cameron said, "there is a very good reason why the long arm of the international law has been looking for this man for such a long time."
In a news release, Interpol called Mladic "Europe's most wanted war crimes suspect."
"The arrest by Serbian police of Ratko Mladic, an alleged architect of human carnage and mass murder, is a triumph for international justice," Interpol Secretary General Ronald K. Noble said in the release.
Amnesty International's senior director of international law, Widney Brown, said, "It took more than 15 years, but at last the people who suffered have hope that he will be brought to justice."
Brown called on Serbian authorities to renew their efforts "to arrest the remaining indicted suspect General Goran Hadzic," who is believed to be in the region, and "bring him to justice."
Madeleine Albright, former U.S. secretary of state, said Mladic's trial "should teach again the grim reality of ethnic cleansing and, I hope, bring some comfort to those who survived."
"Mladic tried to become a conquering hero. Instead, he lived as a fugitive in obscurity and now faces years in custody. Justice works," she said in a statement. "It is a welcome sign that Serbian officials arrested him. An emerging democracy is helping to confront its own past."