The number of foreign fighters entering Iraq and Syria has plummeted over the past year or so, a US general said Tuesday, AFP reports.

Major General Peter Gersten told Pentagon reporters that when he arrived  Baghdad about a year ago, between 1,500 and 2,000 foreign fighters were joining the "Islamic State" (ISIS) group's ranks each month.

"Now we have been fighting this enemy for a year, our estimates are down to 200 (per month) and we are actually seeing now an  increase in desertion rates of these fighters," Gersten said.