The United Nations condemned insurgents in Thailand's deep south Wednesday for seizing a hospital during a recent attack on security forces in the violence-plagued Muslim majority region.

The assault was one of several small-scale but coordinated attacks on Thai forces in the region on Sunday night, following a recent surge in violence by insurgents.

European leaders scrambled Wednesday to salvage an under-fire draft deal with Turkey to ease the migrant crisis with a round of shuttle diplomacy on the eve of a crunch summit.

The 28-member bloc, divided and desperate to end the biggest refugee influx in Europe since World War II, is pinning its hopes on an agreement with Turkish President Recep Tayyip Erdogan.

An Ecuadoran army plane crashed in the Amazon rainforest Tuesday, killing all 22 people on board, President Rafael Correa said.

"There are no survivors," Correa wrote on Twitter, several minutes after first posting news of the crash. "This is a tragedy."

North Korea on Wednesday sentenced an American student who admitted stealing a propaganda banner from a hotel to 15 years' hard labor for subversive activities, state media said.

The judgement was handed down on Otto Warmbier, a 21-year-old student from the University of Virginia, by North Korea's Supreme Court, the North's official KCNA news agency said.

Barack Obama has warned that the 2016 White House race is damaging America's image abroad, sounding the alarm on harsh campaigning that risks eroding gains made during his presidency.

Lashing out at "vulgar and divisive rhetoric" in the race to replace him, Obama told a bipartisan group of lawmakers on Tuesday: "This is also about the American brand."

At least 17 people were killed and dozens wounded on Wednesday when a bomb exploded inside a bus in Peshawar, the main city in Pakistan's insurgency-racked northwest, officials said.

No group has claimed responsibility for the explosion, which happened as the bus carrying mainly government employees was passing through the city's crowded shopping district of Saddar.

Turkey on Tuesday said a female suicide bomber who killed 35 people in Ankara had links to a Syrian Kurdish militia, as security forces clashed with rebels in the restive southeast.

President Barack Obama's White House on Tuesday welcomed Htin Kyaw's election as Myanmar's first civilian president in half a century, saying it was "an important step" in the country's democratization. 

France will tell Turkey at a summit with the EU this week it wants more effective cooperation with Ankara on the migrant crisis, but will warn against any attempt at "blackmail", Prime Minister Manuel Valls said Tuesday.

Brazil's ex-president Luiz Inacio Lula da Silva is about to join the government of his embattled protege Dilma Rousseff, administration sources said Tuesday, as both seek to save their political lives.