Russia's legendary rifle-designer Mikhail Kalashnikov was recovering in stable condition in intensive care Tuesday after being hospitalised with general fatigue, reports said.

An aide to the 93-year-old father of the AK-47 said Kalashnikov had been having heart problems and feeling poorly since March.

"When I visited him at home last week, he told me that nothing seemed to hurt, but that he simply had no strength left," assistant Nikolai Shklyayev told the RIA Novosti news agency.

"It seems that this is just his age showing," Shklyayev said.

Kalashnikov's biographer Alexander Uzhanov told Interfax that he had spoken to the great rifle designer who had given assurances he was feeling fine.

"Mikhail Timofeyevich Kalashnikov told me that he is feeling good and plans to go home soon," Uzhanov said.

Shklyayev said Kalashnikov was sent to intensive care in the central Udmurtia region where he lives and works on Thursday after complaining of general tiredness and swelling -- a frequent side effect of heart disease.

"I last got in touch with (Kalashnikov's) driver. He said that everything was fine," Shklyayev told the Interfax news agency.

The health minister of Udmurtia separately told Interfax that everything was now fine with the region's most famous son.

"There were certain problems," Vladimir Muzlov was quoted as saying.

But now "the situation is normal, stable," the regional health minister said.

Kalashnikov designed his famous rifles -- staples of armies across the world for the past half century -- at the Izmash factory in the central city of Izhevsk and continues to live in the region to this day.

The 205-year-old plant remains one of the main producers of Russian weapons and is treasured as a national icon.

But Izmash has also suffered from dwindling demand and a failure to make up for this with foreign orders -- a problem plaguing many specialised post-Soviet industries.

Kalashnikov and 16 colleagues raised the alarm about the situation at Izmash in an open letter to President Vladimir Putin last month.

They noted that production had fallen to an all-time low and the factory needed to be saved.

The appeal made national headlines and prompted the government to create a consortium called Kalashnikov on the basis of the Izhevsk plant aimed at saving the storied brand.

Popular legend states that Kalashnikov began designing weapons after having trouble with the rifles the Soviet Red Army was using during World War II.

He was the 17th child of family that lived in a tiny village high in the Altai Mountains near Russia's remote border with Mongolia.

He showed an interest in engineering from an early age and enlisted to work as a clerk in a Siberian train station at the age of 18.

He began designing guns army and was assigned by senior officials to help design new rifles and other weapons toward the end of World War II.

He was sent to the Izhevsk plant after the war had finished to complete designs of the first AK assault weapon.

His official biography states that Kalashnikov holds copyrights to 35 inventions and is a member of 16 Russian and foreign academies.