The death toll from a terrorist attack in the south Russian city of Stavropol has risen to 7, an emergencies service official said on Thursday.

An explosive device that went off outside the city's House of Culture and Sport early on Wednesday evening before a Chechen band's concert also injured more than 40 people, with 30 of them remaining in hospital, Stavropol Territory's health minister, Viktor Mazharov, said.

An 11 year-old girl is among the dead.

"Three of them are in a critical condition, nine in a serious condition, 12 people [have] moderately severe injuries and six are in a satisfactory condition. Eight people are receiving out-patient treatment," he said.

Most of the injured are from southern Russian regions.

"One Muscovite [is among the injured], another of the injured has not been identified yet - he is either from Turkey or Azerbaijan," Mazharov said.

The mayor of Stavropol, Nikolai Paltsev, pledged assistance to the affected families.

"The city and regional authorities will provide assistance to all the injured, and pay compensation to the families of those killed. Money will also be allocated from the federal budget. The exact sum of compensation is yet to be established," he said.

Police say that the explosion was equivalent to 0.4 kg of TNT (0.8 lbs).

An improvised explosive device, a gun and ammunition were found during searches of the homes of two people suspected of involvement in the blast, a police source said.

The Stavropol Territory is the largest region in the North Caucasus Federal District, and hosts its administration, but has remained largely free of the violence in the neighboring republics of Chechnya, Ingushetia and Dagestan.

Stavropol Territory Governor Valery Gayevsky said the terrorist attack was aimed at shattering national unity.

No one has yet claimed responsibility for the blast.

STAVROPOL, May 27 (RIA Novosti)