The United Nations rights chief on Thursday accused Czech authorities of systematically detaining migrants and refugees in "degrading" conditions, as part of a policy to dissuade them from entering the country.

Several European countries have in recent months introduced measures to curb the flow of tens of thousands of refugees and migrants on the move across the continent.

The European Union said it will sign next Tuesday a long-awaited accord with Kosovo on closer ties which could open the way to membership for the small Balkan country.

Kosovo declared independence from Serbia in 2008 after years of tensions following the breakup of Yugoslavia in the 1990s.

Turkey was in shock on Thursday after a man threw acid at toddlers at a popular restaurant in Istanbul, injuring seven, media reports said.

A three-year-old was left scarred and partially blind while another six children suffered burns after the man sprayed them with acid in the playroom of the Develi restaurant in the city's upscale Atasehir district, the Hurriyet daily said.

Crimes targeting refugee centers in Germany have risen sharply, police said Thursday, cautioning that the European migrant crisis was also fueling the risk of attacks on politicians by far-right extremists.

The warning by Germany's Federal Criminal Police Office (BKA) comes after a mayoral candidate in the eastern city of Cologne was stabbed in the neck in an attack apparently motivated by her work with refugees.

Pakistan's military said Thursday it had killed 21 militants in air strikes in a restive northwestern tribal area bordering Afghanistan.

The strikes were carried out late Thursday in the Rajgal and Tirah areas of the lawless Khyber tribal district, where Taliban militant and local Islamist groups are active.

A Philippine soldier opened fire on a prayer meeting at a military base on Thursday, killing five of his comrades before troops intervened and shot him dead, an army spokesman said.

Nine other people were also wounded in the rampage at an army camp on the southern island of Basilan, a hotbed for Muslim extremist groups, said Colonel Benjamin Hao.

Over 30,000 people in South Sudan's war-zone regions face death by starvation, the United Nations said Thursday, warning that tens of thousands more are on the brink of famine.

While an official famine has not been declared, the report describes the worst conditions yet seen in a 22-month civil war marked by atrocities and accusations of war crimes, including the blockading of food supplies.

A masked man brandishing a sword and reported to have far-right sympathies killed a teacher and a student and seriously wounded two other people at a school in Sweden Thursday before being shot by police.

Pictures taken by students and circulating in the media showed the assailant wearing black clothes and a Darth Vader-like mask, with school children initially thinking it was a prank or a Halloween costume.

A 15-year-old schoolboy has been detained by police in Turkey for allegedly "insulting" President Recep Tayyip Erdogan, local media reports said Thursday.

The teenager, identified by the initials U. E., spent Wednesday night in a police station after being stopped by officers outside an Internet cafe, Cihan news agency said.

The EU's migration commissioner is to visit new migrant hotspot Slovenia on Thursday to discuss its request for urgent support, as the small nation buckled under a record surge of refugees desperate to reach northern Europe before winter.

Slovenia is now the main entry point into the passport-free Schengen zone on the migrant trail, after Hungary sealed its key southern borders with razor-wire fence to migrants.