WATCH: Blast at Ukraine Rally Kills Two

A blast at a rally in Kharkiv, Ukraine has killed at least two, including a police officer, and injured at least 10.

The rally was intended to mark the anniversary of the Kiev uprising that resulted in the ouster of pro-Russia leader Viktor Yanukovych.

A deal struck earlier this month in Minsk helped a ceasefire take hold, and Kharkiv is not within the contested area, as the BBC reported.

Ukraine’s State Security Service said that the four “terrorists” who carried out the attack were trained in Russia and used Russian-made weapons, as the Kyiv Post reported. And according to Ukraine’s State Security Service senior adviser Markiyan Lubkivskiy, more attacks were in the works:

“[The terrorists] were captured while attempting to attack with a flamethrower a club where soldiers and volunteers gather, as well as a shopping centre.”