A group of militants attacked Grozny, the capital of the Russian federal region of Chechnya, on Wednesday night, leaving parts of downtown still burning. A participant in the attack posted a YouTube video claiming responsibility on behalf of a group tied to the Caucasus Emirate, a jihadist group that has operated in Chechnya for several years. Chechnya fought two failed wars of independence from Russia in the 1990s and endured an Islamist insurgency in the 2000s. But it has been relatively calm in recent years, which makes this attack surprising.

What we know about the attack

The attack began on Wednesday evening when the militants drove into the city center of Grozny in three vehicles and opened fire on nearby police. They then took over a nearby office building, used by local media outlets, and later a nearby school. They fought pitched battles with Chechen security forces that lasted into the morning and left parts of downtown ablaze.

The fighting left at least nine militants and ten security forces dead, as well as an unknown number of security forces and civilians injured. Residents reported hearing what sounded like tank or artillery shells.

Security forces in Grozny told Radio Free Europe reporter Liz Fuller that the militants were from a nearby region of Chechnya. The militants, they said, put on Chechen security services uniforms, called three taxis, "neutralized" the drivers, and then used the cabs to launch the attacks. That was the same tactic used when Chechen insurgents attacked the region's parliament building in Grozny in 2010, the last major attack on the city.

What we know about the attackers

One of participants in the attack posted a YouTube video saying it was a suicide operation ordered by Emir Khamzat, which is the nom de guerre of a Chechen jihadist leader named Aslan Byutukayev.

Khamzat leads a wing of the Caucasus Emirate, a prominent Russian jihadist group that operates in Chechnya and neighboring Russian regions. Khamzat's command is based in southwestern Chechnya, which is where the Chechen security services said the attackers had come from, so it matches up.

Ramzan Kadyrov, the strongman ruler of Chechnya installed by Vladimir Putin, insisted that the attackers had come from outside of Chechnya and the the Caucasus Emirate was too weak to launch such an attack. It's likely that Kadyrov is simply posturing, though, to maintain the fiction that his security services had defeated Chechnya's insurgency.

Where Chechnya's violence comes from

The very, very simple version is this: Russia conquered Chechnya, which is predominantly Muslim, in the early 1800s.

In 1991, the Soviet Union collapsed and many federal regions broke away to become independent countries, such as Belarus and Kazakhstan and others. Chechnya tried to do the same, but negotiations with Russia over formal independence collapsed, the Chechen leader declared unilateral independence, and in 1994 Russian President Boris Yeltsin invaded to keep Chechnya as part of Russia.

That Russian invasion came on December 11, 1994 — exactly 20 years and one week before Wednesday's attack, which hardly seems like a coincidence. This was the start of the First Chechen War, which ended with Russia withdrawing its forces but not granting Chechnya formal independence. In 1999, Chechen insurgents launched the Second Chechen War for independence. The insurgency took on jihadist overtones, and even after Russia won the Second Chechen War, jihadist insurgents kept fighting for years, including by launching horrific terrorist attacks in Moscow. The Caucasus Emirate formed in 2007 as the largest of those jihadist groups.

The jihadist movement has largely waned in Chechnya over the years, in part because its fighters have gone off to Afghanistan and Iraq and Syria, and in part because Ramzan Kadyrov's brutal security forces have put them down — though smothering basic freedoms for many innocent Chechens in the process. It's not clear if this week's attack signals a return of the movement to Chechnya, perhaps as fighters come home from Syria and Iraq, or if this is just a flash in the pan.