African Barrick Gold is being sued in Britain's High Court by a group of Tanzanians who say the company was complicit in the killing by police of at least six villagers at one of its mines in incidents dating back two years.

Law firm Leigh Day said on Tuesday that it was representing 12 villagers wanting compensation for incidents including one, in May 2011, when five young men were killed and others injured.

The company said in response to news of the legal action that it would not compensate illegitimate claims or lawsuits, adding that the May 2011 incident had involved violent intruders who invaded the mine while committing criminal acts.

"In the event any legal proceedings are pursued, African Barrick will vigorously defend itself against all the claims," the company said in a statement.

African Barrick had said in May 2011 that villagers were killed when police came under attack following a raid by hundreds of people at the North Mara mine about 100 km east of Lake Victoria.

Leigh Day said: "The claim alleges that the companies are liable for the deaths and injuries of local villagers, including through complicity in the killing of at least six local villagers by police,"

"It is alleged that police are an integral part of the mine's security and that they shoot at the villagers using tear gas and live ammunition," the law firm said in its statement.

The claimants say that African Barrick, a unit of the world's largest gold producer Barrick Gold Corp, failed to curb the use of excessive force at the mine.

African Barrick, which was due to release second quarter results later on Tuesday, has underperformed its rivals on the stock market and repeatedly cut output forecasts, partly due to illegal mining at the North Mara site.

The company is under pressure to deliver cost savings after a plunge in the gold price and is carrying out a review after Barrick Gold's failed attempt to sell the business to a Chinese buyer.

(Reporting by Sarah Young; Editing by Anthony Barker)