Russia has issued an international arrest warrant for Mikhail Khodorkovsky as Moscow ramped up the pressure on the leading critic of Vladimir Putin.

Earlier this month the investigative committee, which reports directly to the Russian president, charged the former oil tycoon in absentia with organising the 1998 murder of a mayor in Siberia, a move supporters say is aimed at silencing the exiled Kremlin critic.

Khodorkovsky, 52, was also charged with the attempted murders of two other people.

Investigative committee spokesman Vladimir Markin confirmed in a statement on Wednesday that an international arrest warrant had been issued for Khodorkovsky, who lives abroad and spends much of his time in London.

“They’ve gone mad,” Khodorkovsky said in a statement released by his opposition group, Open Russia.

He said an order to have him arrested in absentia compared favourably with a new law that would allow Russian police to fire at women and children.

“And what’s most important, it will be safe for the public,” he said.

His spokeswoman, Kulle Pispanen, dismissed the announcement as political pressure and said it would not affect the former head of bankrupt oil giant Yukos.

“Mikhail Borisovich will by no means limit his movements because of the hysterical actions of the Kremlin ghouls,” Pispanen told AFP, referring to the former business magnate by his first name and patronymic.

Markin on Wednesday reiterated the charges against Khodorkovsky.

Khodorkovsky’s lawyer, Vadim Klyuvgant, said it was up to other countries to decide whether to comply with the warrant.

Speaking on Echo of Moscow radio, he called the arrest announcement “another bout of fraudulent activities”.

On Tuesday, investigators raided the apartments of employees of Open Russia, a group set up to help nurture civil society in the country, as well as its offices.

The searches appeared to be connected to a 2003 case that led to the criminal prosecution of Khodorkovsky, one of Russia’s most powerful oligarchs, and the dismemberment of Yukos, which have become defining events in Putin’s presidency.

The investigative committee has said it is also checking the information provided in foreign courts by shareholders of now-bankrupt Yukos, who are seeking $50bn (£34bn) in damages from Russia and have convinced a Paris appeals court to back the freezing of Russian assets in France.

Khodorkovsky’s staff and supporters ridiculed the raids that took place on Tuesday.

“In revenge for the arrest of Russian property in France, the investigative committee arrested Kulle Pispanen’s MacBook and iPhone, a letter to Father Christmas and a portrait of Khodorkovsky,” Maria Baronova, an Open Russia employee, said on Facebook.

Khodorkovsky spent a decade in prison on charges of tax evasion, fraud and embezzlement, which he and his supporters say were trumped up in revenge for his political ambitions.

He was suddenly pardoned by Putin in 2013 and flown out of the country.

Putin’s spokesman, Dmitry Peskov, insisted on Wednesday that there was no contradiction between the president’s move to pardon the ex-tycoon and the arrest warrant.

When investigators announced earlier this month that they planned to press new charges against Khodorkovsky, he called a news conference in London, saying revolution in Russia was inevitable.

“The investigation is looking into who stole Yukos shares,” Khodorkovsky said on Twitter on Tuesday.

“Let me give you a tip,” he added in a posting with a picture of the Kremlin.