Russia on Thursday arrested and charged the popular governor of a far eastern region on suspicion of ordering the murder of several businessmen 15 years ago, sparking a furious reaction from his party.

The arrest and indictment of Khabarovsk governor Sergei Furgal came after President Vladimir Putin, who has been in power for two decades, this month, oversaw a constitutional vote that allows him to extend his hold on power until 2036.

Furgal is charged with organising "the murders and the attempted murder of a number of entrepreneurs" in 2004 and 2005, said the Investigative Committee, which probes major crimes.

Furgal stood for office representing the LDPR nationalist party and his arrest sparked a furious reaction from its leader.

In televised comments in parliament, LDPR's firebrand leader Vladimir Zhirinovsky said the party's MPs could resign en masse in protest.

"Let the whole world know about the mess happening in the country," he said.

"You are beginning to use Stalin-era methods," he said in a tirade apparently aimed at the ruling party. "If we take to the streets, the Russian Guard will not save you, and the army will be on our side."

He said that Furgal, who was elected Khabarovsk's regional governor in 2018, had been vetted prior to the vote, where, in an embarrassing result for the ruling party United Russia which backs Putin, Furgal secured 70 percent of the ballot.

'Driving Moscow mad'

Furgal, who has nearly 240,000 followers on Instagram, was also a State Duma lawmaker in 2007-1018.

More than 30,000 people signed a petition supporting him after his arrest.

"It's obvious that Khabarovsk region is driving Moscow mad because we do not support United Russia!" one supporter, Yekaterina Vognerubova, said online.

While ostensibly an opposition party, the LDPR usually backs Kremlin initiatives.

Its MPs include Andrei Lugovoy, Britain's chief suspect in the polonium poisoning of former security agent Alexander Litvinenko.

Furgal's detention comes ahead of regional elections in September and some analysts suggested it was a warning to opposition forces.

Two Khabarovsk lawmakers, both members of LDPR, were also detained, Russian media said. The party could not immediately confirm this.

Khabarovsk region had among the highest rates of opposition votes in the nationwide plebiscite, the results of which the Kremlin has called a "triumph."

Flown to Moscow

State news broadcasts showed a group of masked law enforcement officials in camouflage pulling Furgal from the backseat of an SUV in a driveway.

The governor's office said Furgal had been detained near his home as he prepared to leave for work.

He later flew into Moscow under escort where he would be questioned by investigators, Russian news agencies reported.

Moscow's Basmanny district court would consider whether to detain him on Friday, a court spokeswoman told AFP.

Kremlin spokesman Dmitry Peskov said he would "abstain from any comment" on Furgal's performance as governor of the region, which borders China.

According to his official biography, Furgal, a former doctor, was a businessman from 1999 until he took office as a local lawmaker in 2005.

The investigation concerns two murders and one attempted murder, state news agency TASS reported, citing a source.

One of those killed was Furgal's former business partner Oleg Bulatov, who was shot dead in the city of Khabarovsk in 2005.

The other victim, Yevgeny Zorya, was shot dead in the same city in 2004. Both crimes resembled contract killings. The attempted killing was in the neighbouring Amur region.

Investigators said they had arrested four others over the same case.

Russia has a statute of limitation of 15 years for serious crimes, making it hard to see how the case will proceed, wrote RAPSI legal news agency.

Also on Thursday, investigators searched the homes of several Kremlin critics who prepared to stage a rally next week.

On Tuesday, a high-profile former journalist was arrested on charges of treason.