RUSSIA said yesterday the West’s failure to heed its warnings on terror suspects may have led to last week’s Istanbul airport attack.

“Over the past many years, the Russian side has informed our Turkish and European colleagues that persons suspected of being linked to terrorism find shelter both in Turkey and in a number of other European countries,” Kremlin spokesman Dmitry Peskov said.

“In most cases such signals from the Russian side have not been given proper attention or any reaction by our colleagues.”

The triple suicide bombing at Ataturk airport was led by former Chechen separatist guerilla Ahmed Chataev.

Mr Chataev was granted political asylum in Austria in 2008.

Last week Amnesty International refused to apologise for defending Mr Chataev from extradition from Ukraine to Russia in 2010.

Amnesty director for Europe and Central Asia John Dalhuisen said it had opposed the extradition beause Russia was “routinely torturing” terrorist suspects and had not expressed an opinion on Mr Chataev’s innocence or guilt.

Some analysts believe the Istanbul attack was in revenge for Ankara allowing the US to use Syrian and Turkish air bases in its “coalition” bombing of Iraq and Syria.

Turkey is erecting a barrier of giant concrete blocks along its 566-mile-long border with Syria — ostensibly to stop Isis smuggling oil, money, recruits and guns across.

Ankara has denied repeated accusations — often accompanied by photographic evidence — that Turkey is allowing terrorists to cross the border at will.

But documents leaked to the Associated Press by Syrian opposition news site Zaman al-Wasl tell a different story.

The AP analysed 4,037 Isis “entry documents” for recruits entering Syria from Turkey between September 2013 and December 2014.

Around three-quarters of them entered through three particular crossing areas.

They represent between 25 to 40 per cent of the estimated total of foreign Isis recruits — and may only be the tip of the iceberg.

Meanwhile the Syrian government declared a three-day “regime of calm” yesterday, although fighting continued in the village of Madya east of Damascus where the troops were advancing against Syrian rebel group the Army of Islam.