A Mongolian opposition candidate was beaten to death, authorities said Sunday, ahead of parliamentary elections due this month.

The victim was a member of the Democratic Party (DP) and a governor of Sant Sum in central Mongolia, police said in a statement without revealing his identity.

The man was killed on Saturday, police said, adding that the circumstances surrounding the attack have yet to be clarified.

Local media named the man as B. Bayanmunkh, while a statement by his party identified him as "BB".

The DP said it was saddened that "a star of democracy... has lost his life at the hands of others".

"At around 10:00 pm... B was killed by others during a meeting of five members of the MPP in the first round of parliamentary elections," a party statement read, referring to the acronym of the ruling Mongolian People's Party.

Mongolia, which is three times the size of France but has a population of 3.5 million, is due to hold parliamentary elections on June 28.

Violence during election campaigns is rare in the democratic country sandwiched between China and Russia, with all shades of the political spectrum represented in media and confrontational debate commonplace.

But critics say the country is experiencing a declining rule of law and a government seeking to curb criticism of its record on corruption.

"This election is going on under all possible pressures, such as heavy government pressure and spying," the DP statement added.