President Yeltsin's hospitalisation forced him to cancel a radio address and depressed Russian stocks yesterday amid speculation about the gravity of his latest illness, described by the Kremlin as an acute viral infection.
Mr Renat Akchurin, the leading Russian specialist who performed heart surgery on Mr Yeltsin in November 1996, insisted Mr Yeltsin's illness was "absolutely not" linked to his multiple coronary by-pass operation.
Mr Yeltsin's general state of health "does not cause me any alarm or doubt", Mr Akchurin told Interfax, as the Russian leader spent a second day at the Barvikha sanatorium, west of Moscow, where he is due to stay for 10-12 days.
In brief footage shown on Russian television, Mr Yeltsin appeared relaxed as he received the presidential administration chief, Mr Valentin Yumashev, in his private study.
There was no soundtrack on the footage, which showed Mr Yeltsin rising from his desk to welcome Mr Yumashev and then sitting in an armchair.
The Kremlin said Mr Yeltsin (66) was being prescribed anti-inflammatory and anti-viral drugs as well as medicine to boost his general condition.
The US heart specialist, Dr Michael DeBakey, who advised Mr Yeltsin's doctors last year, said in an interview with ITAR-TASS that Mr Yeltsin's current illness "does not arouse serious concern".
But sources quoted by the Washington Post said Mr Yeltsin had been hospitalised due to a new bout of heart trouble. One unnamed diplomat told the newspaper the Russian leader had suffered a heart attack "or something close to it".
The Kremlin spokesman, Mr Sergei Yastrzhembsky, told the Russian RIA news agency that Mr Yeltsin had been advised by doctors not to record a radio address to the nation for Constitution Day today, due to catarrh.
Mr Yeltsin attaches great importance to the constitution, adopted on his initiative in 1993, and the radio address for the public holiday was one of a series of engagements cancelled due to his illness.
The Kremlin spokesman said daily bulletins on the President's health would be released.
A panel of doctors who examined Mr Yeltsin on Wednesday said he was "feeling poorly" and had a temperature of 37.3 degrees Celsius.