MOSCOW – Exiled Russian former tycoon Mikhail Khodorkovsky warned Friday that President Vladimir Putin’s policies on the Ukraine conflict will bring Moscow to ruin, much as the Afghan war helped bankrupt the Soviet Union.

A year after annexing Ukraine’s Crimean Peninsula, Russia finds itself isolated and on a path to self-destruction, said Khodorkovsky, one of Putin’s most outspoken critics. The former oligarch spent a decade in prison on what he said were politically motivated charges.

Khodorkovsky, 51, wrote in the Vedomosti daily that Russian involvement in the Ukraine war a “monstrous” mistake. But he said that the Kremlin leader’s economic system, heavily dependent on state control and export of natural resources, made aggressive foreign policy inevitable.

“War is a natural result of the development of the economic system which Vladimir Putin has been building for the past 10 years,” he wrote in one of Russia’s last surviving opposition dailies.

“War is a portal to hell,” the former head of the now defunct Yukos oil company said. “The result will be deplorable.”

Following a pro-Western revolt against the Moscow-backed government in Kiev last February, Russia seized Crimea and went on to support a heavily armed separatist insurgency in the east of the ex-Soviet satellite.

The West and the new authorities in Kiev accuse Moscow of sending troops and heavy armaments across the border to buttress the insurgency.

Despite evidence of Russian involvement, Moscow denies the claims and now finds itself at the end of tough Western economic sanctions.

Khodorkovsky, who was imprisoned on embezzlement charges after mounting a political challenge to Putin and later released in 2013, compared Ukraine to the debacle in Afghanistan in the 1980s — a war that is widely believed to have hastened the collapse of the Soviet Union in 1991.

“Instead of cultivating huge territory, state leaders decided to seize more land for which they paid dearly,” he said, referring to the Soviet Union’s decadelong invasion of Afghanistan that ended in Moscow’s 1989 withdrawal.

“The invasion of Afghanistan began during the 15th year of Brezhnev’s rule. Crimea and Donbass (eastern Ukraine) happened during the 15th year of Putin’s rule,” the ex-billionaire said.

“When people have been in power for so long, when all checks inside the country have been destroyed, they begin to cross all boundaries — the boundaries of common sense and the borders of neighboring countries.”

He said that Putin’s regime would collapse “within the next 10 years,” but that eastern Ukraine risked instability and chaos even longer.

“There is still no peaceful life in Afghanistan,” he wrote. “There is a high probability that a similar fate awaits eastern Ukraine.”

Khodorkovsky has lived in self-imposed exile in Switzerland since his release from prison.