CNN reports that two large explosions have been heard in the capital of Ukraine, Kyiv.

According to their report, two large explosions lit up the night sky to the southwest of Kyiv early Sunday morning with one detonation that appeared to be approximately 20 kilometers, or about 12 miles, from the city center.

The second explosion rocked western Kyiv just before 1 a.m. local time (6 p.m. ET Saturday) and came from the southwestern part of the city, in the direction of the city’s second major airport.

In other news, the mayor of the Ukrainian capital has imposed an intensified curfew as Russian troops press on the city and is warning that violators will be considered “enemy” saboteurs.

Mayor Vitaly Klitschko says on Telegram that to improve the defense of the capital the curfew will be extended from 5:00 pm to 8:00 am local time between Saturday and Monday.

“All civilians who are on the street during the curfew will be considered members of the enemy’s sabotage and reconnaissance groups,” he writes.

The previous curfew in Kyiv, a city of three million people, had run from 10 p.m. till 7 a.m.