Four people have been killed and two others injured in an explosion at a copper mine in southeast Russia, a Russian news agency reported on Sunday. 

The incident in the town of Gai, in the Orenburg region, occurred during the laying of explosives to extract copper, according to the report.  

Teenage forward Divock Origi turned a listless Belgian performance into a late 1-0 win over Russia on Sunday, enough to qualify for the next round of the World Cup with two straight victories.

Belgium barely contained a reinvigorated Russia for most of the match, yet struck with a blistering final spurt of class and opportunism to turn a bad situation into a wild celebration for coach Marc Wilmots in the 88th minute and hugs all around at the fulltime.

Russian President Vladimir Putin on Sunday called on Ukraine's leadership and rebels to start genuine dialogue, saying Kiev should halt military operations and guarantee the rights of Russian speakers in the separatist east.

"It's necessary to start detailed, substantial dialogue," Putin told reporters on Sunday, adding Moscow would support a peace plan drawn up by the Ukrainian leader.

Ukraine's new Western-backed leader and Russian President Vladimir Putin both called for dialogue Sunday to end a pro-Moscow uprising that has threatened the ex-Soviet state's survival and brought Europe to the edge of all-out war.

The twin calls from the central figures of the worst East-West crisis since the Cold War era both came with conditions and the ragtag militias in Ukraine's eastern rustbelt showing no desire to end their independence drive.

Ukraine's unilateral ceasefire hung in the balance Sunday after clashes engulfed the separatist east and Russian President Vladimir Putin put troops on "full combat alert".

The resurgence of violence in the 11-week pro-Russian uprising threatening to splinter the ex-Soviet state came as Washington accused the Kremlin of covertly arming the rebels and sternly warned Putin against sending troops into Ukraine.

Ukraine's unilateral ceasefire hung in the balance on Saturday as clashes engulfed the separatist east and Russian President Vladimir Putin questioned the new Western-backed leader's claimed commitment to peace.

The resurgence of violence in the 11-week pro-Russian uprising threatening to splinter the ex-Soviet state came as Washington accused the Kremlin of covertly arming the rebels and sternly warned Putin against sending troops into Ukraine.

France and the United States on Friday urged Moscow to help de-escalate the Ukraine crisis or face "new measures" by the Western powers, the French presidency said in a statement.

French leader Francois Hollande spoke by phone with U.S. President Barack Obama and the two called on Russia "to quickly appeal to the armed separatist groups (in east Ukraine) to halt their military actions".

Russia on Friday demanded an apology from Kiev over the "shooting" of a border post from Ukrainian territory that led to the wounding of one customs official, the Kremlin said.

"The Russian side is waiting for an explanation and an apology in connection with this," the Kremlin press office said, according to Russian agencies.

Russian Foreign Minister Sergei Lavrov is expected in Saudi Arabia late on Friday for talks about the Syrian conflict, on which Moscow and Riyadh hold diverging views, a Saudi official said.

Lavrov will meet Saudi Foreign Minister Prince Saud al-Faisal on Saturday in the Red Sea city of Jeddah "for talks on several issues, with developments in Syria at the top of the agenda," the official, who declined to be named, told Agence France Presse.

Russian President Vladimir Putin on Friday offered Iraqi Prime Minister Nuri al-Maliki Moscow's total backing for the fight against jihadist fighters who have swept across the Middle East country.

"Putin confirmed Russia's complete support for the efforts of the Iraqi government to speedily liberate the territory of the republic from terrorists," the Kremlin said in a statement following a phone call between the two leaders.