Russia's RTS index fell three percent at opening on Tuesday, a day after the Standard and Poor's ratings agency stripped the country of its investment-grade rating, cutting it to "junk" status.

The plunge in oil prices and Western sanctions over Moscow's role in the Ukraine crisis have pummelled the Russian economy in recent months, with the ruble collapsing in value.

Irish carrier Aer Lingus on Tuesday backed a 1.35-billion-euro ($1.51-billion) takeover offer from International Airlines Group, parent of British Airways and Iberia.

Aer Lingus announced in a statement that its board was "willing to recommend" IAG's improved proposal -- its third since December -- subject to certain conditions.

World oil prices have fallen too far, the president of state-owned energy giant Saudi Aramco said Tuesday, stressing it was for the market not OPEC producers to shore them up.

"It's too low for everybody," Khalid al-Falih told a conference.

The EU issued Monday a stern warning to Greece that its place in the eurozone was at risk if new Prime Minister Alexis Tsipras failed to meet the country's austerity and debt commitments.

From Brussels to Berlin officials said they were ready to talk to the new government led by Tsipras' radical left party Syriza, but insisted that Athens must stick to existing agreements with its international creditors.

Saudi Arabia's new leadership will push forward efforts to diversify the growing but oil-dependent economy, while easing procedures for investors, senior officials said on Monday.

"The smooth transition of power to King Salman is a testament of the stability and the commitment that our leadership has," Abdullatif al-Othman, governor of the Saudi Arabian General Investment Authority (SAGIA), told a conference.

Spain's recovering economy could grow as much as 2.5 percent this year if oil prices and the euro stay low, the economy minister said in an interview published Monday.

The government says its tough austerity measures have started to strengthen the economy, which officially emerged from recession in 2013 and grew an estimated 1.4 percent in 2014.

German business confidence rose to its highest level in six months in January, as the outlook for Europe's biggest economy continues to brighten, the Ifo economic institute said Monday.

The Ifo institute's closely watched business climate index rose to 106.7 this month from 105.5 points in December, the think tank said in a statement. 

Pakistan's ongoing fuel shortage that has led to worsening power blackouts is weighing on its credit worthiness and hindering its ability to meet key reform targets laid out by the IMF, ratings agency Moody's warned Monday.

The country is currently in the grip of one of its worst power crises in years due to a shortfall in imported oil, with the situation exacerbated Sunday by an attack on a key powerline in restive Baluchistan province.

The euro sank to an 11-year low Monday but Asian equities largely recovered from early losses after an anti-austerity party won Greece's election, throwing its international bailout into doubt and raising fears it could leave the eurozone.

Oil prices resumed their downward trend after rallying on Friday in response to the death of Saudi Arabia's King Abdullah, which fuelled uncertainty in the crude market.

The International Monetary Fund is far from being done with Ukraine, its latest mega-bailout client.

A new aid plan for Kiev -- larger and longer -- is under discussion and raises the risk for the global crisis lender as Ukraine sinks deeper into war against pro-Moscow separatists.