Austrian Chancellor Christian Kern arrives for a cabinet meeting in Vienna, Austria August 30, 2016. REUTERS/Heinz-Peter Bader

REFILE - ADDITIONAL CAPTION INFORMATION Former Serb paramilitary commander Dragan Vasiljkovic (C), known as Captain Dragan and accused of torturing and killing soldiers and civilians during the 1991-95 independence war, goes on trial in court in Split, Croatia, September 20, 2016. PIXSELL/Ivo Cagalj/via REUTERS

Senator Bukola Saraki looks on after being elected as the senate president of the 8th Nigeria Assembly in Abuja, Nigeria June 9, 2015. REUTERS/Afolabi Sotunde

Emma Walmsley of GlaxoSmithKline poses in this undated photograph released in London on September 20, 2016. Courtesy of GlaxoSmithKline/Handout via REUTERS

The remains of a burned tent at the Moria migrant camp, after a fire that ripped through tents and destroyed containers during violence among residents, on the island of Lesbos, Greece, September 20, 2016. REUTERS/Giorgos Moutafis

A banner for communications software provider Twilio Inc., hangs on the facade of the New York Stock Exchange (NYSE) to celebrate the company's IPO in New York City, U.S., June 23, 2016. REUTERS/Brendan McDermid

Migrants stand among the remains of a burned tent at the Moria migrant camp, after a fire that ripped through tents and destroyed containers during violence among residents, on the island of Lesbos, Greece, September 20, 2016. REUTERS/Giorgos Moutafis

A burned shoe is seen on the ground, after a fire that ripped through tents and destroyed containers during violence among residents, on the island of Lesbos, Greece, September 20, 2016. REUTERS/Giorgos Moutafis