Nearly 200,000 antiwar demonstrators took to the streets of Manhattan today, protesting the U.S.-led invasion of Iraq even as bombs rained down on Baghdad again.

Smaller demonstrations took place across the nation, from thousands marching in San Francisco -- where 2,200 have been arrested in recent days -- to several hundred protesters snaking through downtown Washington, chanting "No blood for oil!"

In New York, there were a smattering of pro-war demonstrators, numbering a few dozen. In Louisville, about 400 military wives, leather-clad bikers, veterans and others massed and declared solidarity with U.S. soldiers. In downtown Chicago, a cluster of pro- and antiwar demonstrators faced off outside the Federal Building. Chants of "Killer! Killer!" were met by the response: "Idiot! Idiot!"

There were demonstrations around the globe. About 100,000 demonstrators marched through downtown London, a far smaller number than the 1 million who trooped there for a "Stop the War" rally in February. Polls in Britain have shown that, although support for Prime Minister Tony Blair is rising, about half the population opposes the war. Elsewhere in Europe, about 100,000 marched in Madrid and 40,000 turned out in Berlin. There were rallies in Paris, Rome, Helsinki, Brussels and Lisbon.

The turnout in New York, a march that was 20 abreast and 40 blocks long, surprised some parade organizers. They had worried that the round-the-clock bombing and televised images of U.S. tanks racing across the Iraqi desert might cause antiwar Americans to despair.

Instead, unofficial police estimates of the crowd size grew steadily through the day, and marchers spoke of their determination to be heard.

"It's too late to stop the war, but it's important to register that this is an unpopular war," said Joe Fitzgerald, 45, a musician who marched past Manhattan's tree-lined Union Square with his young child and wife, Deane Beebe. "Our government's reasoning is so nakedly cynical -- one day it's because of al Qaeda, then weapons of mass destruction, then to establish a military presence.

"The pretext for this invasion changes ever day."

Beebe nodded in agreement. She volunteers in her child's public school in Upper Manhattan and says she watches as teachers scrounge for paper and books, and as art classes are cut back.

"I look at all those billions of dollars of high-tech missiles getting dropped on Baghdad," she said, "and I think that children are suffering in both countries while we feed our imperial ambitions."

The New York Police Department markedly scaled back its force compared with the demonstration in February, when thousands of officers lined the street and others on horseback herded demonstrators between steel pens and refused to let them walk down some streets. Overcrowding and frustration led to sporadic clashes and pushing matches, and afterward march organizers criticized Mayor Michael Bloomberg.

Today's march, like February's, was organized by United for Peace and Justice. It was about the same size but a mellower affair. Only one or two officers stood on each corner, supplemented -- according to the NYPD -- by undercover officers with beeper-sized radiation detectors. The mood seemed far more cheerful.

The signs and placards ran the gamut, from "No Blood for Oil" to "Patriots for Peace" to "Support Regime Change: Bomb Texas." Some had a light-hearted tone, such as the leather-clad woman with the many pierced orifices who waved a sign: "I drink Bordeaux and I vote."

But the 65-degree warmth of a spring thaw, and waves and cheers from the crowds lining lower Broadway, could not allay the frustration felt by some demonstrators after months of protests. Not since World War I had so many demonstrators taken to the streets to protest a military action.

But the United States has gone to war anyway, and polls show support for President Bush's decision to invade Iraq rising. Last week, a Washington Post-ABC News poll found 71 percent of Americans support the war.

Many of the marchers had spent the last few nights on their couches, watching TV coverage of bombs and Tomahawk missiles slamming into Iraq.

"There's a sense of frustration, absolutely," said Luis Roman, a legal aid lawyer. "I switched on CNN on Thursday and I haven't turned it off. I worry for both the Iraqis and our soldiers."

Bob Anzelowitz, a PR man for a comedy club, and Sybille Pearson, a playwright, marched through the cool shadows along West Fourth Street. They are veteran peace activists and residents of Manhattan's Upper West Side. They gave no thought to skipping today's protest.

Anzelowitz drew comfort from comparisons to the Vietnam War era, when it took years of strife for so many to march in protest. Pearson agreed.

"I'm here out of necessity," she said. "This is a very different march from the one in February. This one is saying to Bush: Beware. There is a power in this country that will not be silenced."

With the exception of a few radical sectarians -- two dozen hardies from the Sparticist League were on hand to urge a proletarian embrace of international Trotskyite revolution -- no one voiced anything but contempt for Iraqi President Saddam Hussein. And they acknowledged that many Iraqis will draw joy from his overthrow -- providing they are not killed by U.S. bombs.

But they worried that the war will embolden the hawks in the world's only hyperpower -- and encourage future military adventures in Iran and North Korea. And that will sow seeds of hate, they say. Chhandasi Pandya, 21, stood with her friends Shaheen and Saqib in Washington Square Park, after the march.

"Look, it's a double-edged sword," Pandya said "The Iraqi people have lived with pain, and I don't think anyone wants to see Saddam stay in power. But necessarily people in Iraq don't have the time to understand the consequences of America's desire to reshape the world as it pleases."

Fitzgerald, the musician, had much the same thought. He would like to see Hussein go. For a while last fall he thought the United Nations might put enough pressure to force him out. But, to his mind, the United States practiced cowboy blustering instead of diplomacy, and alienated its allies.

The result is a more dangerous world.

"We created an atmosphere of distrust," he said. "And now we've created an air of desperation and fear -- and that breeds terror."

Thousands of people demonstrate in Barcelona yesterday as protests against the U.S.- led war against Iraq swept the globe. In New York, demonstrators marched 20 abreast in a procession 40 blocks long, surprising and pleasing organizers. An unidentified protester is overcome by pepper spray during a rally in New York yesterday where many demonstrators demanded "Peace now!"Andreas Stresemann carries two antiwar signs as he joins thousands of protesters as they rallied down Broadway in New York.