MOSCOW (AP) _ Sacked by a livid Boris Yeltsin amid charges he was plotting a coup, national security chief Alexander Lebed wasted no time Thursday serving his own gruff notice: He will be out to campaign for the ailing president's job.

The Kremlin, rent by power struggles as Yeltsin prepares for heart surgery, turned out to be too small for the aspirations of both these high-powered leaders, who feuded openly during Lebed's four-month stint in the president's inner circle.

Although Yeltsin gained office with help from the widely popular, 46-year-old Lebed, the relationship paid off for Lebed, too. Pursuing his own designs on the presidency, Lebed increased his popularity by reaching a peace agreement with Chechen rebels; he raised his profile by incessantly criticizing _ and infuriating _ his Kremlin peers.

The dismissal came just a day after Lebed's bitter rival for authority in security decisions _ Interior Minister Anatoly Kulikov _ accused him of plotting to form his own 50,000-man army with sights on seizing power in a ``mutiny.''

No evidence surfaced to back this sensational charge, and Yeltsin ignored talk of coups when he announced Lebed's ouster on national television.

Scowling, moving stiffly but speaking clearly and more resolutely than he has in recent appearances, Yeltsin declared that Lebed's unilateral actions, excessive ambition and outspokenness were damaging to the country.

With hands clenched into fists on the table in front of him and eyes narrowed, the president looked angrier than he has in years and healthier and more in command than he has in weeks.

``I can't tolerate the situation any more,'' Yeltsin said, slowly and deliberately signing a decree dismissing Lebed. He spoke at the health spa where he has been resting up for heart bypass surgery next month.

Pegged by many as Yeltsin's likely successor, Lebed was characteristically unbowed. He announced plans to start campaigning soon to replace Yeltsin, who many suspect is too ill to serve out the rest of a term that lasts until 2000. Lebed denied the coup allegations, and has insisted he wants to gain office only through the ballot box.

He said he would not launch his campaign while the president is alive. ``Today he's an elderly and ill person,'' Lebed said. ``It's not for me to kick the one who is down.''

Lebed gave up his seat in the State Duma, parliament's lower house, to take the Kremlin job. The seat has not been filled, and deputy speaker Mikhail Gutsiriyev said Thursday that Lebed could reclaim it.

Lebed's departure could end for now the noisy Kremlin infighting that has created a widespread impression of chaos. But with Yeltsin sidelined from full-time duty until at least early 1997, the government is likely to remain weak, beset by internal bickering and external criticism bound to increase now that Lebed is on the outside.

But the firing creates new obstacles to a lasting peace settlement in Chechnya, where Lebed was the architect of controversial August agreements with separatist leaders that halted 20 months of fighting.

A rebel spokesman said Thursday night that Lebed's dismissal will lead to ``tragic consequences'' for Russia. Ruslan Chimayev told the Interfax news agency that Lebed had fallen ``victim to the `party of war' that seeks a continuation of the slaughter in Chechnya.''

Lebed's signing of a Chechnya accord, criticized by many top politicians as a sellout of the Russian army, only boosted his popularity among Russians who made the political newcomer a surprise third-place finisher in June presidential elections.

In a nationwide survey last month, Lebed was deemed Russia's most trusted politician with more than twice the rating of Communist leader Gennady Zyuganov, who came next. Yeltsin was a distant fifth.

Speaking to reporters Thursday night, the bluntly outspoken Lebed took some parting shots.

He blamed his firing on Yeltsin's strong-willed chief of staff, Anatoly Chubais, who has taken over many of Yeltsin's administrative duties in the president's absence. ``I was very much in his way,'' he said, accusing Chubais of harboring presidential ambitions of his own.

``I honestly tried to do all I could to stop the war, to carry out military reform, to organize a war against crime,'' Lebed said, ``But it's useless when people with rotten cores head law enforcement structures.''

It was the second Kremlin shakeup in four months. The last one, involving the ouster of three top hard-liners in June, came immediately after Yeltsin brought Lebed on board to ensure the backing of the 11 million people who voted for Lebed in the first round of elections.

Since then, Yeltsin has spent only a few hours in the Kremlin as his heart problems worsened. He was hospitalized for three weeks and is now working several hours a day at the Barvikha sanatorium outside Moscow.

In his absence, Lebed has clashed with the president, Chubais, Kulikov and others in a drive to acquire a bigger government role and more power.

Yeltsin complained that Lebed made decisions without consulting the president and the rest of the government. ``There must be a united team,'' the president said. ``The team must be close-knit and work as a single fist.''

Lebed had offered to resign last month, but Yeltsin had encouraged him to be patient, and to learn to get along with the other Kremlin officials. The furor around the coup allegation, however, appeared to be the last straw.

The president fired Lebed after an emergency meeting Thursday of security chiefs called after Kulikov's charge that Lebed was plotting a mutiny. Beefed-up police patrols were visible in Moscow after a Kulikov-ordered security alert.

In a hint of the firing to come, Prime Minister Viktor Chernomyrdin took a slap at Lebed without naming him, blasting ``irresponsibility, incompetence, a home-grown Napoleon complex, that are clearly brimming over, especially lately.''

After the ouster was announced, the prime minister said he approved of the move. ``Boris Nikolayevich (Yeltsin) could have done it earlier,'' Chernomyrdin said. `` I am surprised by his patience.''

But Chernomyrdin also praised Lebed's role as a peacemaker and said the government would abide by the agreements he signed.

In Washington, State Department spokesman Nicholas Burns said only that Lebed's dismissal was ``an internal affair for the Russian government and the Russian people.''