The Complex

American Jihadists in Syria Could Bring Fight Home, U.S. Official Warns

ASPEN, Colo. — The top U.S. counterterrorism official said that the brutal Syrian civil war poses an increasing threat to the American homeland after a recent spike in the number of foreign fighters engaging in the conflict, gaining battlefield experience they could potentially use against the United States and Europe.

Matthew Olsen, the director of the National Counterterrorism Center, told an audience at the Aspen Security Forum that the ranks of foreigners taking part in the war against Syrian strongman Bashar al-Assad now number at least 12,000, up from 7,000 a few months ago, including at least 1,000 Europeans and at least 100 Americans. Olsen said those estimates likely understate the actual numbers.

"The numbers are growing as the conflict there continues," said Olsen, who has run the counterterrorism center for three years and is slated to step down later this year. "It remains a magnet for extremists around the world."

Former FBI Director Robert Mueller, speaking on the same panel, said the intensifying conflict in the Gaza Strip threatened to further "fuel" the ranks of foreign fighters inside Syria. "It may contribute to the number of individuals who feel that they want to become part of the fight, but not necessarily in Gaza," Mueller said.

Neither conflict shows any signs of slowing. Last week included the bloodiest 48-hour period to date in the three-year-old Syrian civil war, with an NGO monitoring the conflict estimating that more than 700 Syrians were killed on Thursday and Friday. More than 170,000 people have died in the conflict since it began in March 2011. Elsewhere in the region, violence flared in the West Bank Friday for the first time since the conflict between Israel and Hamas began in Gaza on July 8. At least five people were killed, pushing the Palestinian death toll to more 800. Israel has lost 35 people, including 33 soldiers.

For the moment, Syria poses the far greater threat to the United States. The Western fighters there on European and American passports could return home to carry out strikes far more easily than other militants could. Olsen said some of those 100 Americans have already come back to the United States, though he emphasized that the FBI is monitoring and tracking many of them.

The counterterrorism chief said that the U.S. intelligence community's persistent difficulty in collecting detailed information about the fighting in Syria made it hard to trace the American and European militants once they made it to the battlefield.

Those challenges continue when the fighters return home. Olsen said it was difficult to identify and track those militants because they included both Syrians living in the United States and fighters from other ethnicities and nationalities. He said the Islamic State, which is leading the fighting in Syria, runs sophisticated English-language websites designed to help radicalize even larger numbers of Westerners and potentially convince them to join the battle.

Olsen said that once there, the militants would find a growing swath of territory inside both Syria and Iraq that is rapidly turning into a safe haven for militants interested in launching attacks both there and elsewhere in the world. He said there were senior al Qaeda leaders in Syria training foreign fighters and taking advantage of their ability to plan attacks elsewhere with little interference.

Syria, Olsen said, was providing safe havens that were starting "to be reminiscent of what we faced before 9/11 in Afghanistan."

Guillaume Briquet/AFP/Getty Images

The Complex

Pentagon: Russia Could Move Heavier Weapons Into Ukraine 'Imminently'

This story has been updated. New information on Russian troop levels at the Ukrainian border was added.

Russia is seeking to escalate the conflict in Ukraine and could move larger, more sophisticated multiple-launch rocket systems into the country to support the separatist rebels as early as Friday, July 25, the Pentagon warns.

"We believe that they're able to transfer this equipment at any time, at any moment," Pentagon spokesman Col. Steve Warren told reporters on Friday.

The United States has been tracking a continual flow of weapons moving across the border and into the hands of pro-Russian separatists over the last several weeks.

"We know that they've transferred tanks, artillery, multiple-launch rocket systems," Warren said. "We have indications that the Russians plan to move larger-caliber rocket systems to the Ukrainian separatists."

There has also been a steady buildup of Russian troops along the border with Ukraine. The U.S. Ambassador to NATO, Douglas Lute, told the Aspen Security Forum Friday that 15,000 Russian troops were amassed along the border with Ukraine.

U.S. officials say that Putin had 28,000 troops deployed along the Russian-Ukrainian border earlier this year, but withdrew all but roughly 1,000 of the soldiers in the run-up to June ceremonies marking the 70th anniversary of the D-Day invasion. Since then, however, Putin has returned roughly 15,000 troops to the border, effectively restoring half of the initial drawdown. 

As for the movement or transfer of surface-to-air missile systems, like the one that shot down Malaysia Airlines Flight 17 on July 17, the Pentagon has no new information. Senior U.S. intelligence officials said this week that they couldn't confirm that the SA-11 missile system that fired on the airliner has been removed from Ukraine, either by the separatists or by Russian forces.

Still, "we're very concerned with the quantity and capability of the weapons flowing from Russia into the Ukrainian separatists' hands," Warren said.

Not only is Russia moving heavier weapons into Ukraine, but it has also been shelling Ukrainian military positions from the Russian side of the border for several days, according to U.S. officials.

"There have been several instances of indirect attacks against Ukrainian military positions," Warren said. "This is unquestionably an escalation from a military perspective, and it flies in the face of everything the Russians have said up 'til now about their desire to contribute to de-escalation."

The U.S. intelligence community has known about this development for several days but only decided to declassify the information on Thursday, according to Warren. State Department spokeswoman Marie Harf was the first to discuss it publicly.

Russia continues to deny the allegations coming from the United States and Ukraine. A spokesman for the Russian Embassy in Washington told the Wall Street Journal: "Unfortunately, it is not for the first time that we hear unproven allegations.... In fact, it is the Russian territory that is being shelled from the Ukraine."

On Wednesday, the Pentagon confirmed that two Ukrainian Su-25 fighter jets had been shot down near the border with Russia.

Alexander KHUDOTEPLY/AFP/Getty Images