PARIS — As investigators follow possible leads from Syria to Greece and Belgium, Friday's deadly and meticulously coordinated assault in Paris was no doubt very much a European attack.

Governments across the continent are busy taking measures to enhance security against a growing threat of similar coordinated terror assaults.

FRANCE
French authorities carried out anti-terror raids in Paris, Toulouse, Lyon, Grenoble, Calais and on the Belgian border in the early hours of Monday morning as they continued their manhunt for the surviving Paris attackers and any accomplices.

The Islamic State (ISIS) claimed responsibility for the horror in Paris that left at least 129 dead. After President François Hollande called the attacks "an act of war," Le Monde reported on the details of the French military launching its largest bombing raid to date in Syria, focusing on several targets in Raqqa, the Islamic State's Syrian stronghold.

BELGIUM
A Belgian-plated car used in the shootings was found in an eastern Parisian suburb on Sunday, and authorities in Belgium scrambled to organize a manhunt for Salah Abdeslam, identified by French police as the man who rented one of the cars. Brussels-based daily Le Soir writes that over the weekend Belgian police conducted raids in Brussels and in the suburb of Molenbeek-Saint-Jean — a hotspot of extremist activity in the past — and arrested seven people linked to the attacks.

The ongoing investigation has established the assault was planned in Belgium, which has become a significant "rear base" for terrorists seeking to strike Europe. The weapons used in August's foiled shooting on a high-speed train traveling from Brussels to Paris and in January's Jewish supermarket shooting in the French capital were obtained in Belgium, and there are 500 Belgian citizens fighting for ISIS in Iraq and Syria.

GREECE
As news spread across Europe that a Syrian passport had been found at the scene of the bombings at the Stade de France, political opposition to the migrant flow into the continent began to swell. French Justice Minister Christiane Taubira announced the passport was fake, but Greek authorities reported the passport holder had passed through the Aegean island of Leros in early October, meaning ISIS militants could have infiltrated the migrant route on their way to Paris.

SPAIN
Madrid-based newspaper El País reports that French police alerted the Spanish government that Abdeslam may have fled to Spain. Madrid stepped up security in response to the manhunt and a string of recent ISIS threats to strike Spanish territory.

ITALY

Rome on Nov. 15 — Photo: Danilo Balducci via ZUMA

While Paris prepares to host the United Nations Climate Conference, Rome has also been a frequent target of ISIS propaganda. Turin-based daily La Stampa reports Italy has heightened security measures ahead of next month's Catholic Church Jubilee celebrations, organized by Pope Francis. Italian authorities recently made several arrests dismantling a large ISIS-affiliated militant network, and 700 soldiers have now been deployed to Rome while special forces units are securing the country's 15 largest cities.

GERMANY
Leading German newspaper Frankfurter Allgemeine Zeitung reports that Chancellor Angela Merkel's political allies in the key state of Bavaria are forcefully insisting on tougher refugee policy after local police arrested a Montenegrin man driving to Paris with a cache of explosives and weaponry last week. The Bavarian finance minister urged Merkel to admit that "open borders were a mistake," and officials in Poland, the Czech Republic and Slovakia have also expressed doubts about the European Union's migrant relocation plan since Friday's events — casting doubt on the bloc's ability to face the challenges of terrorism and rising migration.

UK
The United Kingdom also increased security at its major ports and cities, and British security services joined the French and Belgian investigation into the attacks. A prominent British ISIS fighter known as "Jihadi John" was reportedly killed by a U.S. drone strike in Syria earlier last week, according to The Daily Telegraph, and thousands of troops and special forces have been placed on standby to defend cities in case of a retaliatory Paris-style attack on the UK.

TURKEY, G20 AND BEYOND

G20 leaders in Antalya on Nov. 15 — Photo: Li Xueren/Xinhua/ZUMA

Over the weekend world leaders traveled to the G20 summit in Antalya, Turkey, a country still reeling from a series of bombings allegedly committed by ISIS, including one in Ankara that killed 102 people in October. Istanbul daily Hürriyet writes that Turkish President Recep Tayyip Erdogan and U.S. President Barack Obama discussed further strategies to defeat ISIS in the aftermath of the Paris attacks, just one day after global diplomats in Vienna agreed to a peace plan for Syria.

The plan — negotiated by the U.S., Russia, China, the EU, Iran, Saudi Arabia, Turkey and other Middle Eastern nations, but no party from Syria — calls for a transition government in six months, followed by elections within eighteen months. Despite the world's major powers' agreement on the deal, Syrian opposition leaders flatly rejected the proposal.