The Russian military warned today it may launch ground operations against Islamic militants in Chechnya while warplanes bombed the Chechen capital for a fourth day, pounding industrial and communications facilities.

Four Russian jets flew repeatedly over the city's southern Oktyabrsky district this morning, firing rockets and dropping bombs, the Interfax news agency said. The district is the site of the television broadcasting center destroyed in earlier bombing as well as oil wells.

Russian Defense Minister Igor Sergeyev said he could not rule out the possibility of launching ground operations in the breakaway southern region. Until now, the military has favored an air war that would keep Russian casualties to a minimum.

"There are several variants of a plan for ground operations, which will be implemented depending on the situation that develops," Interfax quoted Sergeyev as saying. He spoke at a Moscow military hospital while visiting soldiers wounded in the neighboring Dagestan region.

"The main aim of all the plans is to eliminate the bandits" and "to create a considerably deep security zone around Chechnya," he said.

The militants are separatists who want to form an independent Islamic nation in what is now southern Russia. The Russian military said the air raids are aimed at preventing militant incursions from Chechnya into Dagestan, where they fought Russian forces this month and last.

Increasingly, however, Russian leaders have vowed to eradicate the militants altogether. Witnesses said that over the past four days, Russian air raids have destroyed more than 100 oil pumps, reservoirs and small refineries in and around Grozny that are believed to be controlled by Chechen rebel field commanders. The oil was the basis of a profitable business providing low-grade gasoline to other Russian regions.

Russian planes also struck suspected rebel camps near Chechnya's border with Dagestan on Saturday, the Russian Tass news agency said, citing the provisional federal press center in Dagestan.

Col. Gen. Anatoly Kornukov, commander of the Russian air force, said in a television interview today that the air campaign against Chechnya could last another month.

Russian military commanders appeared to be considering a major raid into Chechnya to put the militants on the defensive and stop their incursions into surrounding Russian territory. While Russia has massed armored forces on the Chechen borders, military analysts say the force is too small to mount a full-scale invasion of Chechnya.

Meanwhile, Chechens tried desperately to flee the bombing in their region. An estimated 40,000 people arrived in the neighboring region of Ingushetia, prompting the authorities there to close the border today.

On the Chechen side of the border, authorities set up tents for some of the tens of thousands of trapped civilians and brought in piles of firewood.

Chechnya has run its own affairs since winning de facto independence in 1996. Moscow still claims it is a part of Russia and has struggled to keep violence from spreading outward.