isis behind the mask youth recruitment_00002525.jpg
isis behind the mask youth recruitment_00002525.jpg
Now playing
01:40
When typical teens find radical Islam
jihotties isis recruiting brides todd dnt tsr_00000501.jpg
Tumblr
jihotties isis recruiting brides todd dnt tsr_00000501.jpg
Now playing
02:20
ISIS using 'jihotties' to recruit brides for fighters
pkg paton walsh isis children _00024316.jpg
pkg paton walsh isis children _00024316.jpg
Now playing
02:47
ISIS targets the minds of young children
Istanbul attackers are believed to be ISIS members from Dagestan, Uzbekistan, and Kyrgyzstan. Are those countries significant suppliers of ISIS recruits?
ISIS
Istanbul attackers are believed to be ISIS members from Dagestan, Uzbekistan, and Kyrgyzstan. Are those countries significant suppliers of ISIS recruits?
Now playing
02:15
Istanbul attackers connected to Central Asia
brussels jihadi recruitment network mclaughlin pkg_00005025.jpg
brussels jihadi recruitment network mclaughlin pkg_00005025.jpg
Now playing
03:13
Inside Brussels' jihadi recruitment network
jihad 101 elbagir pkg_00023903.jpg
jihad 101 elbagir pkg_00023903.jpg
Now playing
03:49
Jihadi 101: The books at the core of ISIS recruitment
ISIS/Raqqa is Being Slaughtered Silently
Now playing
03:16
ISIS videos show children training to kill
ISIS using child soldiers pkg Walker_00013810.jpg
Kurdistan 24
ISIS using child soldiers pkg Walker_00013810.jpg
Now playing
04:54
ISIS using child soldiers to carry out atrocities
Kashmiri demonstrators hold up a flag of the Islamic State of Iraq and the Levant (ISIL) during a demonstration against Israeli military operations in Gaza, in downtown Srinagar on July 18, 2014. The death toll in Gaza hit 265 as Israel pressed a ground offensive on the 11th day of an assault aimed at stamping out rocket fire, medics said. AFP PHOTO/Tauseef MUSTAFA (Photo credit should read TAUSEEF MUSTAFA/AFP/Getty Images)
TAUSEEF MUSTAFA/AFP/Getty Images
Kashmiri demonstrators hold up a flag of the Islamic State of Iraq and the Levant (ISIL) during a demonstration against Israeli military operations in Gaza, in downtown Srinagar on July 18, 2014. The death toll in Gaza hit 265 as Israel pressed a ground offensive on the 11th day of an assault aimed at stamping out rocket fire, medics said. AFP PHOTO/Tauseef MUSTAFA (Photo credit should read TAUSEEF MUSTAFA/AFP/Getty Images)
Now playing
02:33
ISIS sympathizers inside U.S. a growing concern
teen rescued from isis karadsheh_00001310.jpg
teen rescued from isis karadsheh_00001310.jpg
Now playing
03:12
Teen rescued from ISIS
iraq isis child soldiers elbagir pkg_00004001.jpg
ISIS
iraq isis child soldiers elbagir pkg_00004001.jpg
Now playing
03:47
The children who escaped the clutches of ISIS
isis child soldiers 2 pkg elbagir amanpour _00011419.jpg
isis child soldiers 2 pkg elbagir amanpour _00011419.jpg
Now playing
04:07
Children beaten, killed who refuse to join ISIS
families of isis members intv tsr_00004916.jpg
Emily Kassie/The Huffington Post
families of isis members intv tsr_00004916.jpg
Now playing
01:47
Mothers speak out about their children joining ISIS
fbi warning american female isis fighters brown dnt tsr _00021217.jpg
fbi warning american female isis fighters brown dnt tsr _00021217.jpg
Now playing
02:13
FBI: More women in the U.S. are joining ISIS
Members of Iraqi paramilitary Popular Mobilisation units, which are dominated by Shiite militias, celebrate with a flag of the Islamic State (IS) group after retaking the village of Albu Ajil, near the city of Tikrit, from the jihadist group, on March 9, 2015.
AHMAD AL-RUBAYE/AFP/Getty Images
Members of Iraqi paramilitary Popular Mobilisation units, which are dominated by Shiite militias, celebrate with a flag of the Islamic State (IS) group after retaking the village of Albu Ajil, near the city of Tikrit, from the jihadist group, on March 9, 2015.
Now playing
02:52
Report: Two pilots may have been influenced by ISIS
Washington CNN —  

More than 25,000 foreign fighters have traveled to Syria, affiliating themselves with various groups to fight or support the conflict there, according to the latest assessment of the Office of the Director of National Intelligence.

That is an increase from May, when the number was 22,500, according to Brian Hale, the spokesman for the intelligence office. The fighters come from over 100 countries.

The assessment provided to CNN is the latest estimate since the most recent one was released in early May.

RELATED: Pentagon may lift ban on transgender people

Of that at least 4,500 are from the West, up from 4,000. The 4,500 includes more than 250 from the U.S., an increase from 180 in their last public assessment. These are people who have a claim on legal residence or citizenship in the U.S. This includes U.S. residents who have traveled or attempted to travel to Syria or Iraq to support the conflicts there. It also includes those currently in the region, as well as those stopped from traveling there, or have returned to the U.S.

The U.S. now estimates more than 20 people from the U.S. have died in Syria after traveling there.

In all cases the numbers are estimates at best, Hale said. It may not always be clear if the changes are due to better intelligence, or if the changes may also be due to more fighters actually coming into the area, and in some cases more being killed.

For example, the new estimates shows ISIS can muster between 20,000 to 30,000 fighters across Iraq and Syria, a slight decline from previous estimates of 22,000 to 32,000. The U.S. also estimates the ISIS ranks now include “hundreds of westerners,” and “a few dozen Americans, up from a dozen or more,” Hale told CNN.