Russian energy giant Gazprom on Friday warned Ukraine it could cut off gas exports if the new authorities in Kiev did not pay a bill for debt that now stands at $1.89 billion.

"Ukraine has de facto stopped paying for gas... We cannot deliver gas for free. Either Ukraine pays the debt and pays for current supplies or the risk appears of a return to the situation at the start of 2009," said Gazprom chief executive Alexei Miller, quoted by Russian news agencies.

Spring appears to be arriving early for the German economy as industrial production picked up speed in January, official data showed on Friday.

Industrial output expanded by 0.8 percent in January, after inching up by 0.1 percent in December, the economy ministry calculated in preliminary data.

China's commerce minister on Friday warned industries and companies not to over-expand, after the collapse last year of a key unit of the world's biggest solar firm.

The country's decades-long boom has turned it into the world's second-largest economy and a key driver of global growth, but at the same time major internal imbalances have developed.

In Egypt's newest reality television show, contestants sold fruit juice from push carts in Cairo's busiest market and later organized a desert safari for tourists, hustling to make sales in the capital's crowded streets.

The program, called "The Project" in Arabic, highlights entrepreneurship and small business acumen — something experts say is more crucial than ever as Egypt tries to claw its way out of tough economic times.

Oil prices rose Friday as the Ukraine crisis took a new twist and expectations rose for a solid increase in U.S. employment.

Benchmark U.S. crude for April delivery was up 31 cents to $101.87 per barrel at 0720 GMT in electronic trading on the New York Mercantile Exchange. On Thursday, the contract rose 11 cents to close at $101.56. Brent crude, used to set prices for international varieties of crude, was up 21 cents to $108.31 per barrel on the ICE exchange in London.

Dorian Prentice Satoshi Nakamoto said Thursday that he is not the creator of bitcoin, adding further mystery to the story of how the world's most popular digital currency came to be.

The denial came after Newsweek published a 4,500-word cover story claiming Nakamoto is the person who wrote the computer code underpinnings of bitcoin.

Greece wants more time to shore up its crisis-hit banks, a government source said Thursday, as the authorities were locked in a dispute with EU-IMF creditors on how much it would cost to do so.

"We are asking for more time for the banks," a finance ministry source told Agence France Presse.

China's finance minister suggested Thursday that a growth rate of "7.2 percent or 7.3 percent" would be acceptable, a day after the country announced a 2014 target of "around 7.5 percent".

China is the world's second-largest economy and a key driver of global growth, with its expansion goals closely watched.

Oil prices were mixed in Asian trade Thursday on data showing weaker U.S. energy demand as Russia comes under international pressure following its seizure of Ukraine's Crimea peninsula.

New York's main contract, West Texas Intermediate (WTI) for April delivery, fell 33 cents to $101.12 in mid-morning trade, while Brent North Sea crude for April rose 20 cents to $107.96.

The World Bank announced Wednesday it was resuming talks with the Democratic Republic of Congo on funding for a major hydroelectric power plant.

The talks were suspended in mid-February due to unrest in the Central African nation.