Investors have been trying to guess the timetable for the U.S. Federal Reserve to wind down its massive bond-buying program.

"If you enjoy single player offline, then you can do that and it won't stop working after 24 hours," Jack Tretton said.

Earlier, demonstrators had manned the barricades and prepared for a possible intervention when officers began massing in the area.

“Memory is returning to these lands. It is coming from a far, from the period of nation-building,” Cengiz Aktar said.

President Nicolas Maduro was elected in April to succeed late president Hugo Chavez, who died of cancer after 14 years in office.

Suicide attacks are the signature of al Qaeda's Iraqi affiliate, Islamic State of Iraq, and their growing frequency.

“They will be briefed on the facts of these incidents and our prime minister will listen to their thoughts,” Bülent Arınç said.