Hungary has restarted gas supplies to neighboring Ukraine, Hungarian pipeline network operator FGSZ Zrt said Sunday, after suspending deliveries in September, prompting criticism from Ukraine's state-owned gas firm Naftogaz.

"I can confirm that gas delivery from Hungary to Ukraine has begun," FGSZ spokeswoman Edina Lakatos told Agence France Presse in an email.

Qatar's international reserves hit an all-time high of $46.5 billion (39 billion euros) in November and are expected to climb higher despite falling oil prices, Qatar National Bank figures revealed.

The latest figure was a jump of almost $7 billion on the level of reserves recorded by the energy-rich Gulf state at the same time in 2013.

Oil prices tumbled again Monday, while most Asian stock markets also retreated after a sell-off in New York at the end of last week that came in reaction to data showing weak U.S. wage growth.

The news on wages, which overshadowed another forecast-beating rise in jobs creation, pushed the dollar down against the euro and yen as it complicates the Federal Reserve's plans to hike interest rates.

Venezuelan President Nicolas Maduro has arrived in OPEC's leading oil producer Saudi Arabia, state media reported on Sunday, after he visited Iran to discuss the impact of plummeting crude prices.

Maduro landed on Saturday in Riyadh where Deputy Crown Prince Moqren bin Abdul Aziz received him, the Saudi Press Agency said.

Iran's President Hassan Rouhani, flanked by Venezuelan counterpart Nicolas Maduro, vowed Saturday to "neutralize" the threat posed to both countries by plummeting oil prices, in a barely veiled broadside at Saudi Arabia.

OPEC members Iran and Venezuela are reeling from a slide in the cost of crude to around $50 per barrel from $100 just six months ago, a precipitous fall that is straining their budgets.

Moscow may ask for early payment on its three billion dollar loan to Ukraine, Russian Finance Minister Anton Siluanov said Saturday, accusing Kiev of violating loan conditions.

"Ukraine has violated the conditions of this loan, specifically that Ukraine's public debt does not surpass 60 percent of its GDP," the minister told Russian news agencies.

Cyprus defended on Saturday the decision to halt flights by its national carrier, calling the closure of debt-laden Cyprus Airways "unavoidable", as pilots vowed action against the government.

Government spokesman Nicos Christodoulides told state radio that authorities had tried to rescue the stricken carrier, but that its problems were "long standing" and irreversible. 

Fitch Ratings cut Russia's credit grade Friday to just one notch above junk level, saying plunging oil prices and Western sanctions will force a four percent economic contraction this year.

Fitch lowered its rating for Russian government debt by one step to BBB-, the lowest possible investment grade, and added a negative outlook on the rating.

The dollar fell against the euro and the yen Friday after an otherwise buoyant U.S. December jobs report showed wages sagging even as the unemployment rate fell to 5.6 percent.

The greenback reversed course from recent gains as the slowdown in wage growth in December to 1.7 percent year-on-year, barely keeping up with inflation, pointed to some frailty in consumer spending power.

U.S. Secretary of State John Kerry left late Friday for India on his first foreign trip of 2015, with a heavy focus on trade and investment with the South Asian economic giant.

His tour will also take him to Geneva for talks Wednesday with his Iranian counterpart on Iran's nuclear program, before he makes his first visit as the top U.S. diplomat to Bulgaria later in the week.