KYIV, Ukraine (AP) — Authorities in Ukraine say several regions of the country, including its capital, were facing a Russian missile attack Thursday.

Air raid sirens rang out in many regions of the country early Thursday. In Kyiv, the regional administration said that air defense systems have been activated to fend off the ongoing missile attack. Sounds of explosions were heard in Kyiv.

Ukrainian authorities in several regions said that some Russian missiles have been downed.

Thursday’s attack is the latest in a series of Russian strikes targeting vital infrastructure across Ukraine. Moscow has launched such attacks on weekly basis since October.

In Dnipro, Odesa and Kryvyi Rih regions, the authorities said that they switched off electricity to minimize the damage to critical infrastructure facilities if they are hit.