Serbia's political opposition urged the United States today to ease economic sanctions against Yugoslavia, warning that such measures as an embargo on heating oil are harming ordinary citizens and helping to entrench President Slobodan Milosevic in power.

The appeal, delivered during two days of meetings in Budapest with U.S. special Balkans envoy James Dobbins, sought to persuade the United States that Western sanctions are allowing Milosevic to blame the outside world for the hardships faced by the 10 million people of Serbia--Yugoslavia's dominant republic.

France, Germany and other European Union countries support the idea of removing a ban on commercial air travel to and from Yugoslavia and restoring shipments of food, medical and fuel there--provided that "targeted sanctions" aimed at Milosevic and his associates are sustained. The number of people linked to the Yugoslav ruling clique who have been declared ineligible for visas to nearly all Western nations may soon be doubled to more than 600, increasing the pressure on those closest to Milosevic.

But the Clinton administration has refused to go along with any softening of the sanctions. U.S. officials say they are convinced, given the personal rivalries among Serbian opposition leaders, that the only hope of ousting Milosevic may lie in a massive popular uprising caused by severe deprivation this winter.

"We don't really understand why the Americans are so insistent on these sanctions," said Milan Protic, a leader in the opposition bloc known as Alliance for Change. "There is a serious danger they will backfire by making it a lot easier for Milosevic to stay in power."

Serbian opposition groups want the immediate resumption of commercial air travel connections to Belgrade and basic humanitarian aid, especially fuel oil. They say unless people here receive urgent relief, Milosevic will continue to stir up public resentment against the West--especially now that Russia, despite its own economic difficulties, has started natural gas deliveries.

"The consistent position of all the opposition of Yugoslavia is that the sanctions really are not removing Milosevic," said Milan Panic, a former Yugoslav prime minister. "The humanitarian suffering of people cannot ever justify economic sanctions--Milosevic must be removed by some other means."

Panic said Yugoslavia also needs "massive assistance" to rebuild bridges across the Danube River that were destroyed last spring by a NATO bombing campaign aimed at forcing the Serb-led Yugoslav government to end a violent military campaign against the ethnic Albanian majority of Serbia's Kosovo province.

Serbian Democratic Party leader Zoran Djindjic, who has been staging nightly protest marches with the ostensible goal of forcing Milosevic to step down, said the time had come for a major change in Western strategy. He proposed that the West offer to lift sanctions as soon as free and fair elections are held in Yugoslavia, regardless of the winner.

"We all think this is now the right way to go," Djindjic said. "The opposition alliance is united behind this idea, and so are the major European allies. Only the United States is against it, because the Americans seem to think lifting sanctions would send the wrong message to Milosevic."

Djindjic is locked in a power struggle with Vuk Draskovic, the mercurial head of the Serbian Renewal Movement, for leadership of the opposition drive to bring down Milosevic. Draskovic has refused to join the protest rallies and declined to meet even separately with U.S. envoy Dobbins.

Both opposition leaders, however, insist that sanctions are hurting the cause of the anti-Milosevic effort and have expressed exasperation with the United States for its refusal to ease the economic punishment being inflicted on the population at large.

They argue that such steps are necessary to vindicate contacts with the West at a time when Milosevic is branding them traitors. In a recent speech, Milosevic railed against his rivals as those who "take their marching orders from NATO and are trying to finish the damage started by NATO bombs."