Ukrainian President Petro Poroshenko has declared mourning in Ukraine over the death of eight miners in the Stepova coalmine operated by Lvivvuhillia.

"The Ukrainian president has declared the all-Ukrainian mourning following the tragedy in the Lviv region. The relevant decree was signed today," Ukrainian presidential spokesperson Sviatoslav Tseholko said on Facebook on Thursday.

It was reported earlier eight miners were killed in the rock collapse as a result of an explosion on the 119th conveying belt at a 550-meter horizon of the Stepova coalmine of the Lvivvuhillia company in the village of Hlukhiv, Sokal district, Lviv region at 12.46 p.m. on March 2.