The White House challenged Iranian negotiators on Sunday to "live up to their rhetoric" and strike a nuclear deal with world powers before a March 31 deadline expires.

Iran and six world powers have reached tentative agreement on key parts of a deal sharply curtailing Tehran's nuclear ambitions, Western diplomats said in Lausanne, where negotiators are racing to nail down an accord by midnight Tuesday.

A suicide attacker targeting a prominent Afghan MP killed three people including a child and wounded seven others in Kabul Sunday, officials said, just days after Washington announced it would slow the withdrawal of U.S. troops from Afghanistan.

President Barack Obama last Tuesday reversed plans to withdraw around 5,000 U.S. troops from Afghanistan this year, an overture to the country's new reform-minded leader, President Ashraf Ghani.

The body of a Arsal resident was found decapitated on Sunday in the outskirts of the northeastern border town, more than two months after he was abducted by Islamic State militants.

“The headless corpse of Lebanese citizen Younis al-Hujeiri, who was kidnapped more than two months ago, has been discovered in Arsal's outskirts,” al-Jadeed television reported.

Grand Mufti Sheikh Abdul Latif Daryan called Sunday for pressing on with the bilateral dialogue between Hizbullah and al-Mustaqbal movement, as he suggested expanding it into all-party talks.

“We support the dialogues that lead to positive results that can preserve this country's unity and security and its citizens' piece of mind,” Daryan said.

U.N. Secretary General Ban Ki-moon on Sunday congratulated Nigerians for holding "largely peaceful and orderly" elections despite Boko Haram attacks and urged them to continue to maintain a peaceful atmosphere.

Ban condemned attacks carried out by "Boko Haram and others who have attempted to disrupt" the presidential and parliamentary polls.

Hizbullah on Sunday lashed out anew at “those who don't want dialogue” between the party and al-Mustaqbal movement, blasting them as “instigators and rabble-rousers," as it called for speeding up efforts aimed at securing the election of a new president.

“We know that dialogue can only succeed if both parties want it and this is the case now. Some voices have rejected dialogue and they have become well-known,” Hizbullah deputy chief Sheikh Naim Qassem said.

U.N. chief Ban Ki-moon on Thursday noted that Saudi Arabia was carrying out air strikes in Yemen but steered clear of asserting whether the military action was in line with international law.

Ban recalled that the Saudi intervention was at the request of President Abedrabbo Mansour Hadi, who is considered the legitimate head of state by the U.N. Security Council. 

An Argentine appeals court on Thursday upheld the decision to dismiss a case against President Cristina Kirchner on accusations that she shielded Iranian officials from prosecution over a 1994 Jewish center bombing.

In a 2-1 decision, the court rejected an appeal from prosecutors who sought to revive the case against Kirchner being brought by their late colleague Alberto Nisman before he mysteriously died on the eve of congressional hearings where he was due to present his explosive allegations.

The top U.S. diplomat for Africa will travel to Nigeria to observe presidential elections, the State Department said Thursday, an unusual move for Washington that is closely monitoring the country's Islamist crisis.

Assistant Secretary for African Affairs Linda Thomas-Greenfield will lead an "official diplomatic observation mission" of the presidential and national assembly elections that take place Saturday, according to a statement.

Warplanes from a Saudi-led coalition bombed Huthi Shiite rebels Thursday in support of Yemen's embattled president, who headed to an Arab summit to garner support as Iran warned the intervention was "dangerous."

Defiant rebel leader Abdulmalik al-Huthi slammed the intervention as "unjustified", calling in a televised address for supporters to confront the "criminal oppressive aggression."