The US military on Thursday retreated from a top general's claim this week that the number of foreign fighters joining Islamic State in Iraq and Syria has plummeted by as much as 90 percent.Air Force Major General Peter Gersten, deputy commander for operations and intelligence in the US-led coalition battling Islamic State, told reporters on Tuesday that the number of foreign fighters joining the group had fallen to 200 a month from between 1,500 and 2,000. US Army Colonel Steve Warren, a Baghdad-based spokesman for the coalition, told Reuters that the official estimate is higher than the one Gersten offered, although he did not provide a precise figure."We believe the foreign fighter flow was 2,000 at one point and is now down to a quarter or less of that," Warren said. That would equal roughly 500 fighters per month, or a drop of about 75 percent from the peak."The key is the cumulative effect over time of the damage we have done to them on the battlefield combined with reduced (foreign fighter) flow, so they have to increasingly use younger fighters, conscripts, and security/governance personnel to field their force," he said.It was unclear why Gersten used a figure of 200.US officials, speaking on condition of anonymity had questioned Gersten's remarks. There are multiple signs that the tide of foreign fighters has abated but not that dramatically, they said.The United States and its allies have long tried to track the flow of foreign fighters - which a top Obama aide last week said totaled 40,000 over the war's course - in part because of worries that some could return to conduct attacks in their home countries.