The United States on Friday warned of a dangerous increase in tensions on the undemarcated border between Sudan and South Sudan after reports of clashes between the two sides.

Washington is "deeply concerned" by the reported incidents in disputed border areas between South Sudan's Upper Nile state and Sudan's Blue Nile, the U.S. embassy in Khartoum said.

The U.N. food agency said Friday it aims to provide half a million Malians with emergency food aid this year, especially in the restive north, as a survey showed that nearly all those who have fled the area hope to return home soon.

The U.N. World Food Program aims "to reach around 564,000 people in Mali, (including) more than 400,000 crisis-affected people in the north in Timbuktu, Gao and Kidal in need of assistance," spokeswoman Elisabeth Byrs told reporters in Geneva.

The European Union on Friday announced fresh aid worth 20 million euros to help restore law and order in Mali as well as the return of basic state services such as education after months of trouble.

The aid comes on top of a quarter-billion-euro EU package to also be released as authorities move to restore democracy in the beleaguered west African nation.

The chief minister of Pakistan's restive northwest Khyber Pakhtunkhwa province survived a suicide bombing assassination bid on Friday.

Ameer Haider Khan Hoti was traveling to a political rally when the attacker threw a grenade at his car before blowing himself up, Zaka Ullah, a senior local official, told Agence France Presse, but no-one was hurt.

Japan's Prime Minister Shinzo Abe will hold talks with U.S. President Barack Obama in Washington on February 22, with North Korea high on the agenda, the top government spokesman said Friday.

Abe will leave Tokyo next Thursday on a four-day U.S. visit, accompanied by Foreign Minister Fumio Kishida, who is planning to meet new U.S. Secretary of State John Kerry, Chief Cabinet Secretary Yoshihide Suga told a news briefing.

The United States has designated an alleged senior North African al-Qaida leader a "terrorist" as part of Washington's support of French-led troops who wrested northern Mali back from Muslim extremists.

The U.S. Treasury on Thursday targeted Yahya Abu Hammam, an alleged senior leader in al-Qaida in the Islamic Maghreb (AQIM) with an executive order used to designate "terrorists and their supporters."

U.S. Secretary of State John Kerry is still waiting for Russian Foreign Minister Sergei Lavrov to return a telephone call to discuss North Korea's nuclear test, a top U.S. official confirmed Thursday.

But, three days after Pyongyang's underground explosion triggered global outcry, State Department spokeswoman Victoria Nuland said the new top U.S. diplomat was "relaxed" about the fact that Lavrov had not called back.

North Korea can never be made to abandon its nuclear weapons program, South Korean President Lee Myung-Bak said Friday, arguing that only regime collapse could remove the threat from Pyongyang.

As the U.N. Security Council continues to debate how to punish the North for its latest nuclear test, the outgoing president suggested the best way forward was to try to foment unrest among the North Korean people.

Indian troops shot dead a Pakistani soldier who had strayed onto their side of the de facto border in the disputed Kashmir region, officials from both countries said Friday.

"We detected some suspicious movement yesterday near the LoC (Line of Control) inside our territory and the challengers from our side fired and in the ensuing firefight he was killed," Lieutenant Colonel Rajesh Kalia, a spokesman for the Indian army's northern command, told Agence France Presse.

An 11-year-old boy has died after throwing himself under a train in Japan, in an apparent suicide in protest at plans to close his school, police and press reports said Friday.

The boy, whose name was withheld, jumped onto tracks from a platform at a station in Daito, near Osaka on Thursday afternoon, police said.