African Union chief Nkosazana Dlamini-Zuma warned Monday that a vote in the flashpoint Abyei region claimed by both Sudan and South Sudan was illegal and risked sparking a return to war.

Dlamini-Zuma said the "unilateral act is unacceptable and irresponsible" in a statement that "condemns this exercise in the strongest terms possible".

Fresh violence erupted across Bangladesh on Monday, leaving at least four people dead as rival party activists clashed on the second day of a strike amid a mounting political crisis.

Police said street battles broke out throughout Bangladesh between thousands of supporters of the ruling party and the opposition, which is demanding the prime minister quit and make way for elections under a caretaker government.

Thirty-five bodies in military uniform have been brought to a morgue in Nigeria's restive northeast after a coordinated assault by Boko Haram targeting the security forces, a hospital source told Agence France Presse Monday.

The attack late Thursday in the Yobe state capital of Damaturu was the first raid in a major urban center in several weeks by the insurgent group waging a four-year Islamist uprising.

A former South African minister and ex anti-apartheid activist was briefly detained in the United States because he was on an outdated terror watch list, the ruling ANC said Monday.

Tokyo Sexwale, an ANC lawmaker and a prominent businessman, was detained at John F. Kennedy International Airport in New York last week, the party said, warning that the incident could harm U.S.-South Africa ties.

South Korea on Monday deployed destroyers, jet fighters, attack helicopters and rocket launchers in a major live-fire drill against the threat of North Korea landing troops, the defense ministry said.

"The joint live-fire drill was aimed at repelling landings by enemy forces along the east coast," a ministry spokesman told Agence France Presse.

U.S. security services tracked 60.5 million telephone calls in Spain in a single month, according to a leaked document published in a Spanish newspaper Monday as European outrage deepened over U.S. snooping.

The National Security Agency tracked the origin and destination of the calls and their duration, U.S. blogger Glenn Greenwald said in a story in El Mundo, which published a classified graph of 30 days of telephone call tracing.

Residents of the flashpoint Abyei region claimed by both Sudan and South Sudan were voting on Monday in an unofficial referendum to decide which country they belong to, a move likely to inflame tensions in the war-ravaged region, officials said.

"The people are voting to choose to join South Sudan or to be part of Sudan," Rou Manyiel, chairman of the Abyei civil society organization, told Agence France Presse.

India said one of its soldiers was killed when Pakistan troops fired early Monday across the border in Kashmir, the latest in a series of deadly flareups in the disputed Himalayan region.

The soldier was killed just after midnight at an army post along the northern part of the heavily militarized border that divides the two countries in Kashmir, an Indian army spokesman said.

Colombia's leftist FARC rebels have released a former U.S. Marine after holding him for four months, in a move promptly hailed by Washington on Sunday.

"We welcome the release today of Kevin Scott Sutay from captivity at the hands of the FARC," U.S. Secretary of State John Kerry said in a statement.

At least 10 people were killed on Monday as a fierce storm tore across northern Europe, causing mass disruption to transport.

Four people were killed in Britain and three in Germany as heavy rain and high winds battered the region. Another three died in Denmark, France and The Netherlands.