Russian troops killed up to 40 Chechen rebels in counter-terrorist operations in the Caucasus while Moscow hosted world leaders for celebrations marking victory in World War Two, an army spokesman said on Thursday. Fearing a repeat of Chechen attacks aimed at past May 9 Victory Day parades, authorities introduced tough security measures across Russia before the arrival of more than 50 heads of state, including U.S. President George W. Bush. But army spokesman General Ilya Shabalkin denied any link between the Moscow events and the Chechnya security operation, which ran from May 5 to May 10. "The special operation was not linked to Victory Day festivities. It was a number of local special operations, mainly in mountainous regions," he said by telephone. "We are searching for rebels and we kill those who show resistance."The three days of summitry and ceremony passed smoothly in the Russian capital -- much of which was sealed off to the public -- and the Soviet victory over Nazi Germany was marked across the country without the bloodshed of previous years. A bombing in a Grozny stadium on May 9 last year killed the Moscow-backed leader of Chechnya and six others, while a bombing on the same day in 2002 in the neighbouring region of Dagestan killed 45 people.