Russia's General Prosecutor's office on Thursday ordered a special investigative team to probe the murder of high-profile Chechen politician and former pro-Kremlin lawmaker Ruslan Yamadayev.
Yamadayev was gunned down in central Moscow on Wednesday, reported dpa.
He was the oldest brother in a powerful Chechen clan that has clashed with Kremlin-appointed Chechen President Ramzan Kadyrov.
Business dailies Kommersant and Vedemosti led with headlines calling Yamadayev's murder the death of Kadyrov's greatest enemy.
Kadyurov's spokesman said Thursday the Chechen president was "upset" by the assassination and worried it would be pegged to him.
"Kadyrov was dazed and very upset by the report ... the perpetrators knowing about the conflict between the Yamadayev brothers and Kadyrov were counting on letting the blame fall on the Chechen leadership," Kadyrov's spokesman Lema Gudayev told news agency Itar-Tass.
Yamadayev was shot dead through the window of an armored Mercedes S600 at a red light on the Moscow's ring road, Interior Ministry spokesman Valery Gribakin said in televised statements.
Witnesses said gauze bandages hid the killer's face, Kommersant reported.
Sergei Kizyun, another Chechen war veteran who was also in the car was wounded in the chest and shoulder.
The Yamadayev and Kadyrov clans initially fought for Chechen independence against federal troops in the first Chechen war in the 1990s, but later sided with the Kremlin.
Ruslan Yamadayev and his brother Sulim Yamadayev, who was commander of Vostok, the pro-Kremlin Chechen troop battalion, were awarded country's highest honour, the Hero of Russia medal, by former president Vladimir Putin.
Russian newspapers reported that animosities between Sulim Yamadayev and Kadyrov had culminated in clashes between Vostok and Kadyrov's security forces in April.
Russian military officials have denied the shootout between the rival pro-Kremlin forces.
Sulim Yamadayev was relieved of the command of Vostok last month after being placed on a wanted list in an investigation into the kidnapping and murder of a Chechen businessman and accusation of other killings and tortures by Kadyrov's administration.
The charges have been dropped and before resigning Sulim Yamadayev led Vostok last month in the fighting with Georgian troops over the separatist region of South Ossetia.