(Reuters) - An unidentified individual threw a grenade at a military draft office in the western Ukrainian town of Busk overnight, causing an explosion but not hurting anyone, police said on Monday.

The police said in a statement they were investigating the incident, which comes as Ukraine is stepping up its effort to draft civilians into the armed forces more than 28 months since Russia invaded.

Police in the western Lviv region said the explosion damaged the facade of the draft office and its windows. The individual had fled after throwing the grenade, they said.

There have been persistent cases of men fleeing Ukraine to avoid military service throughout the war. In recent months there have also been Ukrainian media reports of violence directed at draft offices and draft officers.

Asked if they were concerned, Ukraine's military told Reuters that maintaining public trust was an "important component of the activities of the (armed forces), without which it will be extremely difficult to achieve victory over the enemy."

(Reporting by Tom Balmforth; editing by Angus MacSwan)