Twenty-one foreign students were on Thursday in a critical condition in hospital after fire ripped through a student residence in Moscow, an official said.

The 16-storey dormitory, which belongs to one of Russia's top medical schools, caught fire late Wednesday, leaving a total of 43 people in need of medical attention.

Maronite Patriarch Beshara al-Rahi has urged the international community to recognize the Armenian genocide, expressing fears of further such atrocities against Christians in the world.

Al-Rahi, who is in Armenia to attend the ceremony to mark the centenary of the World War I killings by Ottoman Turks, was quoted by the National News Agency as saying on Thursday that “the international community and people with goodwill should recognize the genocide.”

Russia is still expecting North Korean leader Kim Jong-Un to visit Moscow in May, with a possible summit scheduled with President Vladimir Putin, Russia's ambassador to South Korea said Thursday. 

In a press briefing at the embassy, Alexander Timonin confirmed Kim, who has yet to travel abroad since coming to power more than three years ago, was on course to attend Moscow's World War II anniversary celebration on May 9. 

The United States accused Russia Wednesday of building up its forces along the border with Ukraine, boosting air defense systems in the country and training Ukrainian rebels in the east.

"Combined Russian-separatist forces continue to violate the terms of the 'Minsk 2' agreement signed in mid-February," acting State Department spokeswoman Marie Harf said in a statement.

Hackers who penetrated the State Department and White House computer networks in recent months were "Russian speakers," security researchers said Wednesday.

The hackers have aimed at high-profile targets including U.S. government and commercial networks as well as in Germany, South Korea and Uzbekistan, according to researchers at Kaspersky Lab, a Russian-headquartered security firm.

Russia's opposition led by the charismatic activist Alexei Navalny vowed Wednesday to contest next year's parliamentary elections as liberals firm up plans to close ranks amid an intensifying Kremlin crackdown.

Last week Navalny and his Party of Progress  joined ranks with the political party of slain Kremlin critic Boris Nemtsov in a bid to form a democratic alliance and overcome years of bickering. 

President Francois Hollande said Wednesday that France will reimburse Russia if it fails to deliver two Mistral warships in a deal frozen over the Ukraine conflict.

"According to the different scenarios you either have payment or reimbursement," Hollande said during a press conference.

A military rocket has crashed on launch in northern Russia, an official familiar with the situation said on Wednesday, in potentially a new blow to Russia's space industry.

"The military confirmed that their rocket has crashed," an official told AFP on condition of anonymity because of the sensitivity of the situation. 

Dutch investigators have recovered "many" more body parts and pieces of wreckage after resuming their search at the MH17 plane crash site in Ukraine, the Netherlands said Wednesday.

All 298 passengers and crew onboard the Malaysia Airlines jetliner -- most of them Dutch -- died when it was shot down over rebel-held eastern Ukraine last year.

Russian Foreign Minister Sergei Lavrov said Wednesday that the Islamic State group was Moscow's greatest enemy, notwithstanding the strained relations with the United States over the Ukraine conflict.

"I believe IS is our greatest enemy right now," Lavrov said in an interview with Russian radio stations when asked whether he considers China, IS or NATO Russia's greatest threat.