Mikhail Kalashnikov is dead. The humble son of Siberian peasants who never finished school but became world-famous anyway by designing the Kalashnikov assault rifle, the most successful firearm of all time in terms of sales, passed away on Monday at 94.

He died in in his home city of Izhevsk near the Ural Mountains, where his gun is still made. More than 100 million copies of the AK-47 and its many derivatives have been produced since the “Avtomat Kalashnikov-47” entered service with the Soviet Union’s Red Army in 1949.

Kalashnikov’s death was announced by a spokesman for the president of Udmurtia, one of Russia’s federal regions, where Izhevsk is located. The spokesman did not give the cause of death. Kalashnikov was fitted with an electric heartbeat stimulator at a Moscow hospital in June and had been in the hospital in Izhevsk since Nov. 17, state media reported.

Even after the collapse of the Soviet Union, Kalashnikov remained a national hero in Russia. His death prompted immediate messages of condolence from the country’s top leaders, who were often seen with the pluri-decorated Kalashnikov in public ceremonies.

President Vladimir Putin expressed his sorrow at Kalashnikov's passing, calling him an “outstanding weapon designer," said the president's press service, as reported by Radio Echo Moskvy. The last time Putin met with Kalashnikov was last September in Izhevsk, when the president stopped by the famed weapon inventor's home.

Prime minister Dmitry Medvedev posted on his Facebook page, "The passing of Mikhail Trofimovich Kalashnikov is a tremendous, irreparable loss for our country. The legendary weapon maker devoted his whole life to the service of his homeland and to bolstering its safety. We will remember this extraordinary person."

At a lavish Kremlin ceremony on Kalashnikov's 90th birthday four years ago, then-President Dmitry Medvedev bestowed on him the highest state honor -- the Hero of Russia gold star medal -- and lauded him for creating "the national brand every Russian is proud of."

Kalashnikov said pride in his iconic invention was mixed with the pain of seeing it used by criminals and child soldiers.

The photos below show Mikhail Timofeyevich Kalashnikov in recent years, with his weapon and with different Russian leaders.

Maria Bromberg contributed reporting for this story.

Kalashnikov A Kalashnikov in September 2007 in a field near his native village of Kurya in Russia's Altai region. Photo: REUTERS/Andrei Kasprishin

Kalashnikov B Russia's President Vladimir Putin (L) meets Kalashnikov in Izhevsk September 18, 2013. Photo: REUTERS/Michael Klimentyev/RIA Novosti/Kremlin

Kalashnikov C Kalashnikov arriving at the house of his niece in his native village in Siberia, September 2007. Photo: REUTERS/Andrei Kasprishin

Kalashnikov D Kalashnikov toasts with Russia's President Dmitry Medvedev during festivities to celebrate his 90th birthday at the Kremlin in Moscow, November 10, 2009. Photo: REUTERS/Natalia Kolesnikova/Pool

Kalashnikov E In Caracas with a translator after attending a Venezuelan independence day event with Venezuela's President Hugo Chavez, July 5, 2006. Photo: REUTERS/Francesco Spotorno

Kalashnikov G In his Russian Lieutenant-General's uniform, at the launch of his 'Kalashnikov Vodka' brand in London, September 20, 2004. Photo: REUTERS

Kalashnikov I With then-Russian President Boris Yeltsin, who had just given him a medal. Moscow, December 1998. Photo: REUTERS

kalashnikov J Getting a kiss from then-prime minister of Russia Viktor Chernomyrdin, Moscow, 1997. Photo: REUTERS