TOKYO — Two popular Russian sumo wrestlers were slapped with lifetime bans from Japan's ancient national sport for allegedly using marijuana, and the head of the Japan Sumo Association resigned today to take responsibility for the scandal.

The wrestlers, brothers Roho and Hakurozan, tested positive for the drug when the sport conducted its first drug tests following the arrest last month of another Russian wrestler, Wakanoho, for marijuana possession.

Roho, whose real name was listed by the association as Boradzov Soslan Feliksovich, is in sumo's top division, while Hakurozan — who was listed as Baradzov Batraz Feliksovich — is in the next-highest tier.

The scandal has rocked the sumo world, which has its roots in religious ritual and tends to hold its athletes and officials to high moral standards. Marijuana possession is considered a serious offense in Japan, and the scandal has been front-page news.

The punishment was handed out at an emergency meeting of top sumo officials Monday, according to the Japan Sumo Association.

Kitanoumi, the association's chairman and Hakurozan's mentor, also told the meeting that he would resign to take responsibility. Kitanoumi is a former grand champion wrestler who is considered by many to have been one of the best ever.

Kitanoumi will be replaced by another former wrestler, Musashigawa.

Sumo wrestlers in Japan are usually known by a single fighting name.

Sumo's current crisis began last month with the arrest and subsequent lifetime ban on Wakanoho, whom police said had a small amount of marijuana in his wallet. Wakanoho, whose real name is listed by the sumo association as Soslan Aleksandrovich Gagloev, was the first wrestler ever to be ejected from sumo for drug use.

The association then held tests on all 69 of its top two division wrestlers and found Roho and Hakurozan had tested positive for the drug.

A second test was done by a Japanese laboratory internationally certified to conduct doping tests. Results released Friday showed the two consumed the drug in amounts far beyond what could be inhaled from secondhand smoke, sumo association spokesman Yuichi Ida said.

Roho and Hakurozan have repeatedly denied using the drug.

Police have questioned the two wrestlers and searched their rooms. It was not immediately clear if any further legal action would be taken. Unlike possessing or selling the drug, it is not illegal to be found to have used it.