Turkey must open Syrian border, HRW tells world leaders

"Turkey casts a dark shadow over the World Humanitarian Summit in Istanbul, as its border guards have killed Syrian asylum seekers and pushed others back into the world's worst warzone," said Gerry Simpson, senior refugee researcher at Human Rights Watch.

"Governments and UN agencies should end their deafening silence on Turkey's abuse of Syrian asylum seekers and press Turkey to reopen its border to civilians fleeing the horrors in Syria."

The World Humanitarian Summit starts on Monday in Turkey to discuss the future of humanitarian aid.

Turkey, host to 2.7 million Syrian refugees, has tightened restrictions along the Syrian border in the past year, only allowing in critically wounded refugees.

Turkey has long promoted the concept of a "safe zone" inside Syria, where people fleeing the fighting could go instead of entering Turkey.

As part of its controversial migration deal with Ankara to curb refugee and migration flows to Europe, the EU has pledged to work with Turkey to create in Syria "areas which will be more safe" for "the local population and refugees to live".

Turkish border guards have pushed back and fired at Syrians trying to reach Turkey in recent months, according to HRW reports. Ankara denies any wrongdoing.

"As host of the World Humanitarian Summit, Turkey should be setting a positive example on the treatment of people at its borders and not trapping them in a warzone," Simpson said.

"It has been a year since Turkey shut down its border to the world's most war-ravaged people, and it is well past time for the world's leaders to speak up."