NEW YORK, NY - OCTOBER 23, 2014: A health alert is displayed at the entrance to Bellevue Hospital October 23, 2014 in New York City. After returning to New York City from Guinea where he was working with Doctors Without Borders treating Ebola patients, Dr. Craig Spencer was quarantined after showing symptoms consistent with the virus.

A physician with Doctors Without Borders who returned to New York City after treating Ebola victims in West Africa tested positive for the virus on Thursday, setting off fresh fears about the spread of the disease.

Muslims perform Eid al-Adha prayers outside the Central Mosque in Bangui, Central African Republic on October 04, 2014.

Gunfire, explosions heard in capital amid tension between militias.

A banner calling for the safe return of the 43 students missing in Ayotzinapa, Mexico, hangs from the fence of the Mexican embassy in Buenos Aires on October 22, 2014.

Faced growing criticism since the disappearance of 43 students.

Taro Aso speaks during an event at the World Bank October 9, 2014 in Washington, DC. Participants gathered to discus universal healthcare.

Meeting in Beijing fuels talk of meeting between leaders.

Christophe de Margerie, chief executive officer of Total SA, pauses during the Freedom and Solidarity Forum in Caen, France, on Thursday, June 5, 2014.

Christophe de Margerie had been chief executive of Europe's third largest oil company since 2007.

A photo taken from the Suruc district of Sanliurfa, Turkey shows smoke rises from Ayn al-Arab city (Kobani) of Syria after the US-led coalition bombed the targets of the Islamic State of Iraq and the Levant (ISIL) in Ayn al-Arab, on October 7, 2014.

The U.S.-led coalition has carried out its most sustained air attacks so far on Islamic State fighters attacking the Turkey-Syria border town of Kobane.

Members of US private security company, Blackwater.

Guards guilty of killing 14 Iraqis in a square in Baghdad in 2007.