Despite of global efforts to reduce the flow of willing converts to the Islamic State group's ranks, an estimated 30,000 recruits have crossed the Syrian border to fight alongside ISIS, the New York Times reported. That estimate is double the amount tallied last year, when it was estimated that 15,000 fighters had jumped the border from 2011 to 2014.

That includes an estimated 250 Americans who have made the trip to Syria and Iraq to join the fight, about 150 more than a year ago. Countries around the globe have been trying to cut the flow of foreign fighters going to the war zone and joining ISIS by increasing intelligence sharing and tightening borders.

The news comes just days before U.S. President Barack Obama is expected to address the United Nations Tuesday, taking stock of the current state of affairs in the war against ISIS. On that same day, Congress is expected to release a bipartisan report evaluating the efforts to stop foreign fighters from joining ISIS. That investigation concluded efforts to do so largely have failed.

The failed efforts by the Obama administration to stop the flow of Americans joining the ranks of ISIS is compounded by other setbacks in the overall anti-terror effort. A $500 million program aimed at producing militants capable of taking on the Islamic State produced a very limited number of fighters and the latest reports indicated a group of those fighters turned a quarter of their weapons over to al Qaeda offshoot the al-Nusra Front in exchange for safe passage. Russia has been increasingly defiant of U.S. pressure and has been building up warplane bases in Syria. Also, the retired four-star general currently serving as the diplomatic envoy in the area recently announced he will be stepping down at the end of the year.

This is not, however, the first report indicating Americans and foreign fighters are making their way into ISIS's hands. FBI Director James Comey told Congress in July an estimated 200 fighters at the time had made the trip from the United States. "These threats remain among the highest priorities for the FBI and the intelligence community as a whole," Comey told a group of senators.

The fight against ISIS has cost the United States an estimated $3.8 billion so far, the Pentagon estimated. That price tag comes to $6.5 million spent every day on surveillance and airstrikes. The U.S. has conducted more than 7,000 airstrikes to combat ISIS.