Over the weekend, Russian-led separatist forces took control of most of the ruined airport in Donetsk, forcing a final retreat by Ukrainian forces. Hours later, separatists launched a deadly rocket attack on the port city of Mariupol, killing 27 civilians. The fatalities only add to a ten-month conflict that has left 5,000 civilians and many more Ukrainian security forces, separatists, and Russian combatants dead.

The most recent round of bloodshed—which started in late January in the Donetsk region and was coordinated with terrorist attacks, first on a Kharkiv courthouse on January 19 that injured several people and, the next day, on a train line in Zaporizhzhya as a cargo train was crossing—follows efforts by Russia over the winter to establish a more coherent separatist military force out of a multitude of warring groups. The centerpiece of this strategy was stationing up to 10,000 forces in the Dontesk People’s Republic and the Luhansk People’s Republic, both of which declared independence from Ukraine in a May 2014 referendum.

Russian President Vladimir Putin’s goal for these troops is simple. He wants to rebuild “New Russia,” the Tsarist empire's term for the eight Russian-speaking regions of eastern Ukraine (Dnipropetrovsk, Donetsk, Kharkiv, Luhansk, and Zaporizhhya) and southern Ukraine (Kherson, Mykolyiv, and Odessa), to assert influence over Kiev’s domestic and foreign policies. In some regions, such as Dnipropetrovsk, Kherson, Mykolayiv, and Zaporizhzhya, New Russia never really took off. Indeed, Dnipropetrovsk has been a key rear guard for the Ukrainian military and National Guard. After street battles in the strategically important Kharkiv and Odessa regions, pro-Ukrainian forces defeated New Russia plans in the spring. In the last few months though, pro-Russian groups that were pushed underground have resorted to terrorism.

Now, with the new offensive in the Dontesk and Luhansk People’s Republics, Moscow is looking to decisively win the battle in the Donbas (the name for these two regions) by propagating terrorism and political instability across Ukraine. The terrorists’ training takes place at Novaya Rus (New Russia) coordinating centres in the Russian cities of Belgorod, Tambov, Taganrog, and Rostov; in Moldova’s frozen conflict zone of Transdniestr; and in Crimea’s port of Sevastopol, home of the Black Sea Fleet. Captured terrorists from the Svat group, who were active in the Mariupol region, have testified to attending training camps in Sevastopol. There, they say, they were taught how to build bombs, wage guerrilla urban warfare, and conduct reconnaissance and intelligence operations behind enemy lines. The Russian military intelligence service (GRU) and Russia’s Federal Security Service (FSB) lead the training.

At their training, the terrorists are given five strategic goals. First, blow up train lines and key government buildings, launch small-scale hit-and-run attacks on offices at military–industrial plants, and bomb pro-Ukraine rallies, military recruiting centres, and National Guard training facilities. Second, destabilize the country and provoke panic using whatever means at hand. The third goal is to collect intelligence on the movements of Ukrainian armed forces and National Guard battalions to help plan future terrorist attacks. Fourth, terrorists are supposed to establish underground print shops to publish pro-Russian separatist leaflets and newspapers. And finally, they are told to infiltrate Ukrainian National Guard battalions.

The training, to some degree, is working. So far, the terrorist attacks have been concentrated in four key areas: Kiev, where Russia can menace the weak Ukrainian government; Kharkiv and Odessa, the swing regions; and the port city of Mariupol, which would be key to any Russian attempt at establishing a land bridge from Russia to Crimea.

Kharkiv, which is next door to Donetsk, was the scene of street battles in March of last year between pro-Russian groups, including “political tourists” that were bussed in from Russia, and pro-Ukrainian forces. (In a PBS Frontline episode called “The Battle for Ukraine,” a pro-Russian vigilante who had been trained by Russian intelligence said he was paid $40 per hour to beat up “Ukrainian fascists”—that is, supporters of the Euromaidan). From late February, after the Euromaidan took place in Kiev, and throughout the month of March, a pro-Russian paramilitary organization called Oplot led anti-Euromaidan and pro-Russian rallies in the city and attempted to take control of key government buildings. After a shoot-out between Ukrainian nationalists and Oplot that killed two Oplot militants, the city’s mayor, Hennadiy Kernes, refused to jail the Ukrainian nationalists. The move angered Oplot, which is suspected of attempting to assassinate him the following month.

In April and May, Ukrainian special forces, led by Interior Minister Arsen Avakov, who is from Kharkiv, got the upper hand over Oplot. Most of the militant group’s members then moved to the Dontesk People’s Republic, where some have continued to operate underground. They have trained their sights back on Kharkiv. Recent attacks have targeted the city’s prosecutor’s office, a military hospital, a furniture factory owned by a Euromaidan activist, and a pub named Stina. An underground explosives and printing factory in the region was closed down in October and a number of separatist organisations were banned.

In Odessa, there was some calm between early May, when street battles between pro-Ukrainian and pro-Russian forces led to over 40 deaths (mainly of pro-separatist activists who died in an accidental fire at the Trade Union building), and September, when Ukraine and Russia signed a peace agreement. But, since then, the battle has reignited. A group of five terrorists were detained in Odessa in September; they had been trained in Russia. A second group of detained terrorists had planned to copy last spring’s violent seizure of state buildings in the Donbas. In December, a terrorist accidentally blew himself up before planting a bomb at a military academy. Other targets have included Euromaidan civil society support groups who collect supplies for Ukraine’s military, shops owned by these activists, train lines, and freight cars transporting oil.

Finally, in Mykolayiv, the Donetsk region’s only port, which is critical for creating a land bridge from Russia to occupied Crimea, there have been terrorist attacks against bases of the Azov National Guard battalion, the port, and important local factories. Some captured terrorists have explained that they are responsible for helping Russian and other eastern forces target incoming rocket attacks. Rebels played just such a role in this weekend’s missile attack on the port; Ukraine’s security service published wiretapped conversations of the terrorists discussing the mission.

The examples go on and on: Ukraine’s security services have captured terrorist suspects in the West of the country, Central Ukraine, and other regions of Eastern and Southern Ukraine. In Kharkiv and Odessa, the terrorist campaign has destabilized the cities and, at the end of the year, Ukrainian National Guard units were brought in to assist the regular security service root out terrorist cells. A counterterrorism operation this month in Kharkiv, following a bomb explosion that injured many people, detained Oplot terrorists and closed down an underground pro-separatist print shop. For now, Ukrainian security forces are successfully keeping control over terrorism in Kharkiv and Odessa, but it remains unclear how long they can do so.

Ukraine has also requested compensation from Russia for its aggression and asked the United Nations to condemn the country for breaking the International Convention for the Suppression of the Financing of Terrorism, which was adopted by the UN in December 1999. It has likewise demanded that the International Criminal Court and European Court on Human Rights (ECHR) charge Russia with financing and supporting terrorism. Indeed, the government has already sent three specific claims to the ECHR charging Russia with supporting and arming violent groups in the Donbas, annexing Crimea, and tampering with Ukrainian-owned businesses and state structures there. Ukraine’s government believes that Russian occupation authorities have stolen billions of dollars of Ukrainian state and private assets.

Ukraine’s demands for justice should not be ignored. The Donbas separatist groups do, indeed, fit the definition of terrorist groups, especially after the Mariupol rocket attack. And there are multiple sources that point to Russian training and military support for them.

Of course, Washington has been reluctant to call the Donbas separatist groups terrorists or recognize the Donetsk and Luhansk People’s Republics as terrorist states, as Ukrainian President Petro Poroshenko requested during his October visit to Washington DC. Doing so would inevitably push the Untied States to put Russia on its list as a state sponsor of terrorism alongside Iran, Sudan, and Syria. The EU would be obliged to follow suit, and tougher sanctions would follow. For the last few months, the West has viewed the further escalation of tensions with Russia as unwise.

But the Mariupol attack could change that calculation. Soon after it, U.S. Secretary of State John Kerry blamed Russia for the carnage, as did the NATO general secretary. With Russia blatantly ignoring every article of the Minsk peace accords it signed with Ukraine and with it supporting a two-pronged military and terrorist campaign against and inside Ukraine, the United States and the European Union should reassess their stance. It is time to call Russia what it is: a state sponsor of terrorism.