In a new video posted online, Russia's most wanted terrorist called on his followers to use "maximum force" to put a stop to the planned 2014 Winter Olympics in Sochi in southern Russia.

Doku Umarov, the head of the Caucasus Emirate, which seeks to establish an Islamist caliphate in the Russian Caucasus, said his group is ending its 18-month-old moratorium on attacks inside Russia following what it called increased Russian state violence against its civilians.

"They [Russians] plan to hold the Olympics on the bones of our ancestors, on the bones of many, many dead Muslims, buried on the territory of our land on the Black Sea, and we as mujahideen are obliged to not permit that, using any methods allowed us by the almighty Allah," Umarov said in the video, according to Reuters.

"I call on you, every mujahid, either in Tatarstan, Bashkortostan or on the territory of the Caucasus to use maximum force on the path of Allah to disrupt this Satanic dancing on the bones of our ancestors," he added.

Umarov, sometimes referred to as "Russia's Osama bin Laden," has taken responsibility for some of the biggest attacks inside Russia, including the 2011 bombing of a Moscow airport that killed more than 30 people.

Sochi, which lies on the Black Sea near Russia's southern border with Georgia, is 300 miles east of the Chechen capital of Grozny, nearly a third the distance to Russia's capital in Moscow.

Russian security officials downplayed Umarov's threats to Russia's state-owned RIA Novosti.

"Despite calls by various gang leaders… active in certain regions of the North Caucasus, all of Russia's state institutions, special services and law enforcement bodies are constantly implementing a set of measures aimed at providing security for Russian citizens," said a statement from Russia's National Anti-Terrorist Committee (NAK).

The 2014 Winter Games games were already expected to take place with security on alert both ahead of and during the competition.

U.S. Homeland Security Secretary Janet Napolitano and other U.S. officials were in Vladivostok, Russia, today for the 4th Annual International Conference on Security Matters hosted by the Russian Security Council.

She told attendees that back in May, she met with Russian Internal Affairs Minister Vladimir Kolokoltsev in Washington, where they discussed, among other things, "information sharing in support of security for the Sochi Winter Olympics in 2014."

"With regard to security, our nations share a strong commitment to countering terrorism and violent extremism," she said in prepared remarks today.

Napolitano also "wished the Russian government a successful 2014 Olympic games in Sochi, and reaffirmed the United States' commitment to working with the games' Russian hosts to ensure a secure event," a Department of Homeland Security statement said.

ABC News' Lee Ferran and Mike Levine contributed to this report.