The capital of the semi-autonomous Russian province of Chechnya saw its worst fighting in years this week when a group of militants stormed a series of buildings and police checkpoints. The raid by a Chechen Islamist group left 21 wounded and 16 dead, including three Russian police officers.

It was the second terrorist incident in the city of Grozny in weeks. In October, five police officers were killed, and 12 others wounded when a suicide bomber detonated a device after approaching a checkpoint in the city.

Recent events suggest that a new offensive by Islamist militants is underway in the North Caucasus, a region rocked by two devastating wars in the late 1990s. Overnight in the neighboring province of Dagestan, offices belonging the Russia’s domestic security and intelligence agency FSB were set ablaze. It is not immediately clear if this incident is related to the terrorist acts that shocked Chechnya in recent weeks, but it would not be a surprise if they were.

With Islamist movements across the region lining up to declare their fealty to the Islamic State, some are beginning to ask if these renewed attacks have their roots in the Sunni insurgency spreading across the Arab world from Benghazi to Baghdad.

“Inevitably, some of this may have been exaggerated in social media. But there is no question that a new battle has begun in an old war that Moscow—and many in Grozny—had hoped was over,” wrote Anna Nemtsova in The Daily Beast. “Analysts also are raising the possibility that the so-called Islamic State, widely known as ISIS or ISIL, may have, at a minimum, ideological links to the attackers.”

The editor-in-chief of the Caucasian Knot Internet site, Gregory Shvedov, told The Daily Beast on Thursday that the assault on Grozny was one more episode in series of terrorist incidents in Chechnya this year: “The underground intends to demonstrate that the existing security system is not effective,” Shvedov said. “We reported a split in the ‘Caucasus Emirate’ with some insurgents joining ISIS.” But it is not clear if the latest action is at the hands of that faction or another. “There is still a question who really was behind the current attacks,” said Shvedov.

Russia has been preparing to meet threats from ISIS to materialize in the North Caucuses after ISIS-linked militants threatened to attack the region in retaliation for Moscow’s support of Syrian President Bashar al-Assad.

Via al-Arabiya:

In the video, that was banned on YouTube in Russia but was still available on other platforms, ISIS fighters threatened Bashar al- Assad and Russian President Vladimir Putin, promising to “liberate Chechnya and the Caucasus.”

The ISIS militants in the video say that Assad’s weapons will be turned against him and add that Russian equipment was used to bomb ISIS fighters. One ISIS militant says he would like to convey a message to Putin, telling the leaser that ISIS will liberate Chechnya and the Caucasus and saying that Putin’s throne will be threatened by ISIS.

If ISIS is opening a new front up against Russia, they will soon learn that the Russian Federation prosecutes anti-terrorist campaigns ruthlessly and with little regard for civilian life. It may be the biggest mistake ISIS has ever made in a series of strategic miscalculations.