Human Rights Watch said in a report published on Saturday that it had documented several cases of Turkish border guards shooting at Syrian refugees trying to cross into Turkey from May to December last year.

The report said Turkish guards also shot at refugees while they were still in Syria, killing 10 people, including a child.

It also points to accounts of abuse by detained asylum seekers, including forced return to Syria and withholding medical care.

Turkey's presidential spokesman, Ibrahim Kalin, said later on Saturday that the allegations will be investigated, adding it was "unlikely" Turkish soldiers would shoot at people and pointed to Turkey's open-door policy.

Turkey is hosting nearly 3.5 million Syrians who have fled the civil war.

Deadliest day in Afrin

Meanwhile, at least seven Turkish soldiers were killed near Afrin in the deadliest day since Ankara's operation started in the Syrian Kurdish enclave.

Operation "Olive Branch" was launched on January 20 against the Syrian Kurdish People's Protection Units (YPG), which Ankara says are an offshoot of the outlawed Kurdistan Workers' Party (PKK), but which have been working closely with the US to fight "Islamic State" (IS) in Syria.

In a statement on Saturday, the Turkish military said five soldiers had been killed after their tank in Syria came under attack near Afrin.

Three Turkish soldiers were reported killed in the offensive earlier in the day, putting the total death toll for Turkish troops since the operation started on January 20 at 14.

The army statement said the Syrian Kurdish militia and the IS group carried out the attack.

Ankara said almost 900 YPG fighters have been killed so far.

jbh/jlw (AFP, AP)