Russian investigators said Thursday the latest failure of the Proton-M space rocket happened on May 16 could be caused by a subversion act.

"We can't rule out the option of a deliberate act of sabotage," the Interfax news agency quoted chairman of the investigative commission Alexander Danilyuk as saying.

He said the commission made that conclusion following its inspections of a rocket plant in the central Russian city of Voronezh, as well as of two other space industry enterprises involved in Proton-M's construction and assembly.

"The commission hasn't found any violations during production cycle there which could cause such a malfunction," Danilyuk said.

Among other versions under consideration he named destruction of a fuel pump in the Proton's third stage.

The investigative commission includes representatives of the Federal Space Agency Roscosmos, Defense Ministry, Space Forces, rocket-space corporation and other related organizations.

A Proton-M rocket carrying an Express-AM4R communication satellite had an engine problem at the 540th second after launch at the Baikonur space center in Kazakhstan.

On July 2, 2013, another Proton-M rocket with three Glonass-M navigation satellites aboard exploded less than one minute after lift-off at Baikonur.