Late in the day Greece asked for official talks with European authorities and the International Monetary Fund, a step that could lead to the release of billions of euros from a standby aid package agreed on over this past weekend.

The yield spread of 10-year Greek government bonds against German Bunds closed slightly wider at 413 basis points, but was much tighter than the session's 436 basis point high.

The euro was on track for its biggest one-day fall against the dollar in three weeks, down 0.78 percent at $1.3545.

China's growth buoyed oil prices early but the stronger dollar tempered the rally and crude hovered below $86 a barrel.

The MSCI index of global stocks rose to an 18-month high, and a pan-European index of regional shares closed at its highest level since September 2008.

The FTSEurofirst 300 index of top European shares closed up 0.6 percent at 1,112.22 points.

Wall Street traded mostly flat.

The Dow Jones Industrial Average was down 9.15 points, or 0.08 percent, at 11,113.96. The Standard & Poor's 500 Index was down 1.37 points, or 0.11 percent, at 1,209.28. The Nasdaq Composite Index was up 4.17 points, or 0.17 percent, at 2,509.03.

Spot gold prices rose $5.55 to $1,159.40 an ounce.

US oil prices edged lower in choppy trading on Thursday. Front-month US crude for May delivery was down 26 cents at $85.58 a barrel at 1:17 p.m. EDT (1717 GMT), after ending 2 percent higher the previous day. ICE Brent crude for May rose $1.06 to $87.21 a barrel on the day of its expiration.

On a technical basis, prices may be due for a small correction on Thursday but upward momentum is set to stay intact.

OPEC has signaled it is eyeing oil's recent jump to 18-month highs. Kuwait's oil minister said Thursday that OPEC would make a decision on an output boost to calm oil prices if prices moved above $100 a barrel.

On Tuesday, OPEC delegates said a price above $90-$95 would prompt the group to consider raising output.

But Venezuela's Oil Minister Rafael Ramirez said on Thursday that OPEC will not increase output to bring down prices as inventories are high because demand is low and any additional output would end up in stockpiles and not go to consumers.

US crude oil futures settled at $86.86 on April 6, the highest settlement since the $88.95 close on Oct. 8, 2008. The April 6 intraday high of $87.09 was the strongest intraday peak since $89.82 was struck on Oct. 9, 2008.