ROSTOV-ON-DON, June 21 (RIA Novosti) - Police in southern Russia have prevented 30 planned terrorist attacks since the start of the year, the country's deputy prosecutor general said Thursday.

Ivan Sydoruk said police had disarmed 148 gunmen of illegal armed formations, and killed 39 militants since the beginning of the year. However, he said the situation in the North Caucasus remains difficult, with heavy casualties among law enforcers.

Since the start of the year, "45 law enforcers have been killed and another 55 policemen wounded in Chechnya and Dagestan," the official said.

Sydoruk said 11 extremist crimes have been reported in the Southern Federal District since the beginning of January, 20% more than in the same period of last year.

The Astrakhan Region and the Krasnodar and Stavropol territories reported the most alarming results, he said.

Sydoruk said the work of local prosecutors during the first half of the year was not faultless. "In particular, we have failed to prevent numerous violations in criminal investigations," he said.