Stallone: Losing Expendables 2 stuntman 'very hard'

Sylvester Stallone (right) is currently promoting the action sequel with Arnold Schwarzenegger

The death of a stuntman while filming action sequel The Expendables 2 was "very hard" to deal with, its star Sylvester Stallone has said.

"The stunt team took it very, very hard and shut down for quite a while," the 66-year-old told reporters while promoting the movie in London.

"It's happened twice before on films I've been on and it's never easy."

Kun Liu was killed last October while filming in Bulgaria. Another performer, Nuo Sun, was seriously injured.

"Our hearts go out to the families and those on the production affected by this tragedy," the producers said in a statement released at the time of the "unfortunate" accident.

The accident happened in October during the filming of an explosion on an inflatable boat on Bulgaria's Lake Ognyanova.

Kun Liu's parents are seeking unspecified damages from production companies Millennium Films and Nu Image, and the movie's stunt co-ordinator Chad Stahelski.

Jason Statham (left) and Dolph Lundgren are also part of the cast

Stallone's visit to the capital follows the passing of his own son Sage, who was found dead in Los Angeles last month at the age of 36.

The Expendables 2, a sequel to Stallone's 2010 box-office success, is released in the UK on Thursday.

Like its predecessor, the film sees the Rocky and Rambo actor joined by a host of 1980s action stars for a revenge mission motivated by the death of one of their number.

Arnold Schwarzenegger, Bruce Willis and Dolph Lundgren all feature in the film, while Belgium's Jean-Claude Van Damme is cast against type as its villain.

China's Jet Li and Britain's Jason Statham also feature as members of Stallone's team of mercenaries, while martial artist turned actor Chuck Norris makes a cameo appearance.

Speaking on Monday, Schwarzenegger said he had believed the first Expendables - in which he made his own brief cameo - was "impossible to top" but felt its follow-up was "bigger and better".

The film marks the Terminator star turned politician's return to full-time film-making following the end of his seven-year tenure as governor of California.