Jailed Russian billionaire businessman Mikhail Khodorkovsky has issued a rallying cry to supporters to create a new political elite of "honest heroes".
Khodorkovsky is in a penal colony where prisoners do hard labour
In a full-page advertisement in the UK's Financial Times newspaper, he describes the current Russian authorities as a criminal bureaucracy.
He accuses them of trying to isolate and physically destroy him, but warns that the fight is just beginning.
It is unclear how he issued the statement from his Siberian jail.
The former head of Russian oil giant Yukos is serving an eight-year prison sentence in a penal colony for economic crimes. The tycoon, once Russia's richest man, was convicted of tax evasion and fraud.
The colony in Krasnokamensk, in the eastern Chita region close to the Chinese border, is about 4,700km (3,000 miles) east of Moscow.
Critics accuse him of ripping off his homeland's natural wealth for personal gain. His supporters say the case against him was politically motivated and he is paying the price for his political ambitions and links to opponents of President Vladimir Putin.
In the advertisement, Khodorkovsky says the Kremlin has tried to isolate him from his "country and its people" and "to physically destroy him".
"By doing so, today's Russian government has proven once again that it's not ready for an open and honest discussion with me (or for any straight talk with the opposition," he says.
"They hope Khodorkovsky will be forgotten."
In his appeal to his supporters, he says Russia faces enormous challenges, needing to rebuild the army and legal system.
"Create from scratch a new breed of officials - those interested in the fate of the country and its people, not their own unbridled personal enrichment," he instructs them.
"We need to step off the dead-end path to making Russia a simple source of raw materials, to make the decisive turn in the direction of a new knowledge-based economy."
The BBC's Stephen Eke says that although the specific policy ideas the advertisement contains are not different from the liberal agenda Khodorkovsky espoused before he was sent to jail, the language is.
Our correspondent says this suggests the advertisement comes from the lips of his allies Leonid Nvzlin, Vladimir Dubov and Mikhail Brudno - all, like Khodorkovsky, Jewish, current or former billionaires, and one-time oligarchs but now in self-imposed exile in Israel.
Earlier this week, they held a press conference to warn of what they said was a plot to "physically eliminate" Khodorkovsky.
They also accused President Vladimir Putin of personal enrichment at the expense of society.
Our correspondent says many ordinary Russians, who tend to view the oligarchs as the robber-barons of Russian capitalism, would find that hypocritical.
The latest available poll suggested that two-thirds of Russians had absolutely no sympathy for Khodorkovsky, and four-fifths were uninterested, or totally uninterested, in what he had to say.