The Pentagon’s Joint Staff warned in a recent intelligence briefing that Islamic State terrorists are entering Europe "mostly unimpeded," according to defense officials.
The briefing last week by the J-2, as the joint staff’s intelligence directorate is known, outlined both legal and illegal methods being used by terrorists to gain access to the continent.
Recent Stories in National Security
The briefing included a title slide that read "ISIL traveling to Europe mostly unimpeded," and warned that European security measures have minimally impeded the flow of terrorists. ISIL is an alternative name for the terrorist organization, which is also known as ISIS.
Additionally, the refugee flow from Syria to Europe is overwhelming counterterrorism efforts there, raising new fears that refugees from Syria being settled in the United States pose a security threat in this country.
"That ties directly to security efforts here," said one official familiar with the briefing who spoke on condition of anonymity.
A Joint Staff spokesman declined to comment on the briefing. The J-2 provides intelligence to Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, and Secretary of Defense Ash Carter, as well as to U.S. commanders.
According to the International Organization for Migration, a Geneva group, a total of 868,282 migrants have reached Europe since January, most of them through Greece from Turkey.
On Sunday, European and Turkish leaders concluded an agreement that seeks to reduce the refugee flow. Europe will provide $3.2 billion in aid in return for tightening its borders from the refugee outflow. Some 2 million Syrians fled to Turkey as a result of the conflict.
Turkish authorities detained 1,300 migrants on Monday, a sign of the new policy, Agence France Presse reported from Istanbul.
President Obama has accused Republicans of Islamophobia and charged them with being "scared" of refugees from Syria. He also said anti-immigration sentiment was fueling terrorism.
The Islamic State’s ideology is based on creating a caliphate and defeating its perceived enemies in the West. In recent weeks, the group’s propagandists have stepped up calls for attacks on what it terms "crusader" western nations such as France, Germany, and the United States.
In his Thanksgiving Day message, Obama called on Americans to support his policy of accepting Syrian refugees and said none will be admitted "until they undergo the highest security checks."
"That was the case before Paris and it’s the case now," Obama said.
Earlier, after meeting his security advisers, Obama said U.S. authorities are doing "everything possible to prevent attacks at home and abroad, and to prevent foreign terrorist fighters from entering the United States or other nations."
The House passed legislation Nov. 19 with bipartisan support that would add new security review procedures for Syrian refugees before they are admitted to the United States.
Republican presidential candidate Sen. Ted Cruz (R., Texas) has introduced legislation that would bar any refugee from a country with territory controlled in substantial part by the Islamic State, al Qaeda, or other designated terrorists.
"After the horror of Paris, it would be downright reckless not to take basic steps to protect ourselves from the threat of terrorist infiltration," Cruz stated in a recent Washington Times op-ed. "It takes just one jihadist to cause enormous damage and take countless lives. This is a small, first step toward protecting America, and I will never apologize for defending this nation."
The military intelligence assessment follows the Nov. 13 terrorist attack in Paris that investigators say involved one Islamic State terrorist who infiltrated Europe through Greece by posing as a refugee.
A Syrian passport belonging to a man named Ahmad Almohammad was found by investigators with one of the three terrorists who blew themselves up outside France’s national stadium.
The passport revealed the terrorist entered Greece from Turkey on Oct. 3 and then traveled through Serbia and Croatia. The other attackers were identified as having European citizenship.
The passport is believed to be one of the 3,500 blank Syrian passports seized by the Islamic State when it took over the Syrian town of Raqqa.
According to European authorities, the Islamic State also obtained passport-production machinery and stamps used to validate them. The passports have been sold to smugglers in Turkey, who have sold them to Syrian refugees.
The Paris case indicates the group is using the passports for its terrorist operations.
Refugee routes into Europe typically follow a path from Turkey to Greece, then through the Balkans and into the rest of Europe, including Germany.
Other refugee streams include migrants coming by boat from Libya to Italy.
European press reports also have revealed that Muslim extremists are infiltrating Europe through Bulgaria, with the assistance of organized crime groups that can provide terrorists with forged identity documents.
Islamic State terrorists have used the Bulgarian network, including a reported safe house in the capital of Sofia, to gain access to Europe. Their tactics have included using the forged documents to travel to Tanzania or a Scandinavian country before entering France or Germany—considered key Islamic State targets.
Security analysts say the Islamic State likely has created sleeper cells in Europe, like the one that carried out the Paris attacks. Investigators say that group was linked to Islamists in Toulouse and Belgium.
The FBI is urgently pursuing U.S.-based Islamists in an effort to uncover any sleeper cells of the Islamic State.
So far, most of the jihadist terrorist strikes in the United States appear to have been carried out by Islamic State sympathizers with no direct links to the Syrian and Iraqi terror group.
The former chief of staff of the Czech Republic’s army warned last week that jihadists are using the wave of migrants to gain entry to Europe for attacks.
Gen. Jiri Sedivy told the Prague newspaper Provo that Germany’s intelligence service recently disclosed that Islamists were targeting refugee camps as a recruiting ground for terrorists.
A video posted on YouTube by Islamic State supporters Sunday showed the entrance to a U.S. military base in Germany. A man speaking Arabic in the video called for "victory" to Islamic State fighters in Iraq and Syria.
Meanwhile, Germany’s Der Spiegel magazine reported that the suspected organizer of the Paris attacks, Abdelhamid Abaaoud at one time lived in a house in Syria with several members of a German group affiliated with the Islamic State called the Lohberg Brigade, with members coming predominantly from the North-Rhine Westphalia region.
An Israeli counterterrorism center reported that Abaaoud, who died in a police raid in Paris five days after the attacks, highlights the threat posed by Syrian foreign fighters who return to their homeland.
"The mass-killing terrorist attack in Paris, carried out with the involvement of European ISIS operatives, is a clear illustration of the threat presented to
Western Europe by ISIS foreign fighters who return to their countries of origin," the Meir Amit Intelligence and Terrorism Information Center stated in a report.
"The terrorist attack in Paris indicated that ISIS has identified their potential, and has begun sending them to the West to establish terrorist networks and to carry out terrorist attacks," the report said, noting the terrorist suicide bomber at the stadium had been sent from Syria.
The terrorism center noted that Abaaoud gave an interview to the Islamic State’s English-language magazine Dabiq in February that sought "to encourage European operatives to return to their native countries for terrorist missions."
A short time after Abaaoud said he evaded security authorities in Belgium and returned to Syria he was directed, probably in March 2015, to return to Belgium to plot the Paris attacks, the report said.