Emirati authorities have detained a Russian national in connection with the killing of a former Chechen rebel leader, a police official says.

Russian media reports said Sulim Yamadayev died on Monday, two days after he was shot in a midday attack outside the seaside residential complex where he lived in Dubai.

Major-General Dahi Khalfan Tamim, Dubai's police chief, told the Reuters news agency that police are investigating the incident and have a suspect in custody.

"Nevertheless, the case is clear and there is no confusion over what happened. An organised criminal group was behind the assassination."

Tamim also rejected Russian media reports that said Yamadayev had survived the attack.

"He was shot and died instantly on the scene."

Longtime rivals

Yamadayev was a Chechen rebel who switched allegiances in the Chechen conflict and became a decorated Russian officer.

A longtime rival of Ramzan Kadyrov, Chechnya's Moscow-backed leader, Yamadayev had challenged Kadyrov for control of Chechen security forces.

"We hope that law enforcement agencies will find the killer," Ali Karimov, a spokesman for President Kadyrov in the Chechen capital, Grozny, said.

Karimov did not elaborate on the incident.

Yamadayev left Russia after his brother, Ruslan, was shot and killed in central Moscow last September.

Russia has waged a brutal war against Chechen separatists since the 1990s.

The violence began when a former Soviet air force officer seized power and declared independence after the collapse of the Soviet Union.

Russia eventually allowed former rebels who switched sides to take over the local Chechen government.