The decaying bodies of foreign jihadists are piling up among the ruins of Mosul where the last few dozen Islamic State group fighters are mounting a desperate last stand.

More than three quarters of the remaining jihadists in Mosul are foreigners, according to Iraqi commanders who have reported a spike in suicide attacks as anti-IS forces close in on the Old City.

"They never surrender," said General Abdel Ghani al-Assadi, a commander in Iraq's elite Counter-Terrorism Service.

"Old Mosul will be their graveyard."

It was in Mosul in July 2014 that IS supremo Abu Bakr al-Baghdadi made his only public appearance, to urge Muslims worldwide to move to his "caliphate", proclaimed less than a week earlier, straddling Iraq and Syria.

Thousands of foreigners responded to his call.

According to Iraqi police and army commanders, most of the foreign IS fighters still in Mosul in recent months came from Russia, particularly Chechnya, and other former Soviet bloc countries, as well as various Arab states.

Then come Muslims from Asia -- Afghans, Pakistanis, Uighurs from China -- as well as Europeans from France, Germany, Belgium and Britain, along with Americans, the same sources said.

They are also believed to include a few dozen jihadists from other French-speaking countries.

"Most of them come from countries such as Algeria, Morocco or Tunisia," said General Abbas al-Jabouri, a commander of the police Rapid Response force.

Pale, hungry civilians who managed to escape from the Old City described the foreign fighters as cruel men who detained them in houses, many of which were bombed out.

- Iraqi jihadists flee -

When Iraqi forces launched an assault on the Old City on June 18, foreigners accounted for only 20 percent of the 1,200 jihadists identified at the time, according to army officers.

But most Iraqi jihadists have fled by mingling in with the flood of civilians fleeing the Old City.

The army says many were arrested, but officers privately estimate that several hundred were able to slip through the cracks.

Foreigners though would be "arrested immediately" during exit screening, says Lieutenant Colonel Haider Hussein, instantly recognisable because of their poor grasp of Iraqi Arabic.

An Iraqi officer is more blunt: "When we see them, we kill them".

In May, the Wall Street Journal reported that France had asked Iraq to hunt down and eliminate 27 French jihadists in Mosul to prevent them returning to Europe.

France, as well as the Iraqi commanders, denied the existence of such a list.

But Assadi said: "All IS fighters who do not surrender must be killed, whatever their nationality."

According to several Iraqi officers, Western intelligence services take DNA samples from the bodies of jihadists.

At the beginning of the battle, eight months ago, the jihadists preferred ambushes, snipers and car bombs. Then, in the narrow streets of the Old City, they sent more and more suicide bombers.

In the last areas where they are now entrenched, sometimes with their families, "they wait in the houses, and when our forces enter, they open fire or blow themselves up," said Hussein.

"That's the only strategy they have left."

Source: AFP