Turkish troops have reportedly shot and killed at least 16 Syrian refugees who attempted to cross the border to escape the Syrian conflict, the London-based Syrian Observatory for Human Rights said Thursday.

The monitor said refugees were killed on different occasions over the past four months, including at least three children.

“It’s in all areas. It happens to people coming from Idlib, Aleppo, Isis areas, Kurdish areas,” a spokesperson for the Syrian Observatory told The Independent.

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In one incident, the group said Turkish forces allegedly killed a man and his child at Ras al-Ain, at the eastern end of the Turkish-Syrian border. Also, the monitor claims that two refugees were killed on March 5 by Turkish troops in Guvveci on the western part of the Turkish-Syrian border.

Meanwhile, one unnamed refugee smuggler who works at the border told the British newspaper The Times that refugees attempting to cross the border would now “either be killed or captured”.

“Turkish soldiers used to help the refugees across, carry their bags for them. Now they shoot at them," he added.

He also warned that the number of refugees killed could be much higher than what the Syrian Observatory claimed as many of those killed by Turkish security forces are buried on the Syrian side of the border where record keeping could prove more difficult.

For the first few years of the Syrian conflict, Turkey had an open-border policy that saw millions of Syrians crossing the border and welcomed in. Refugee camps at the border were hailed by several aid groups as a successful model for how nations should treat refugees.

However, this policy was criticized because many saw it as turning a blind eye to fighters going into Syrian territories and joining rebel groups including extremist ones.

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The news comes days after Turkey and the European Union finalized an agreement that would see Greece returning refugees arriving at its eastern shores to Turkey while Ankara would receive more than US$4 billion in aid and visa-free entry into the EU for its citizens starting June.

However, for the EU to return refugees to Turkey, the country has to be labeled a “safe third country”. Recent reports of attacks on refugees by Turkish forces could cast doubt over such labels and fuel further criticism of the controversial deal.