ARIS, Oct. 8 — European expressions of support for the military campaign begun by the United States and Britain in Afghanistan continued to roll in today. There were also scattered demonstrations in several countries that deplored the use of powerful air strikes against such a poor country.

Spain and Italy joined France and Germany in pledging to send troops, if necessary. NATO agreed to send five Awacs early warning planes and crews to the United States to free up American surveillance aircraft for use in the campaign against Osama bin Laden and the Taliban.

"There is no lack of enthusiasm for this campaign," the secretary general of NATO, Lord Robertson, said after a quick vote of support by the 19-member alliance this morning.

For the most part, newspaper editorials supported the start of the military campaign. But many continued to urge American restraint, applauding what they viewed as a tempered approach so far.

"Yes to targets that hit the Taliban regime," a French daily, Libération, said. "Yes to everything that can contribute to isolating the bin Laden network. But let no one tell us that a devastated country like Afghanistan has thousands of targets that would necessitate massive and long bombardments."

Some newspapers questioned whether a military campaign could be effective. A Spanish daily, El Mundo, headlined its editorial "An attack that is justified but of uncertain efficiency."

"Serious doubts remain that the actions initiated yesterday can really finish off the terrorist threat and people like bin Laden," the paper said.

Most countries had stepped up security after the Sept. 11 attacks on Washington and New York. Several countries continued to bolster precautions.

"We have to be ready for an isolated act of violence, probably against an American or British building," Interior Minister Otto Schily of Germany said on television.

In Italy, Pope John Paul II offered a prayer for peace.

In recent days, polls have showed wide support in Europe for the United States and its campaign, as long as the action does not last too long or result in the deaths of innocent civilians.

In the last 48 hours, governments have stepped up their support, too. On Sunday night, France and Germany said they were prepared to send troops, if necessary. Today, Italy and Spain said they were, too.

In Spain, a spokesman for the government, Pío Cabanillas, said Madrid was absolutely ready for its military to take a more active role.

Prime Minister Silvio Berlusconi of Italy said his country was "ready to take part in any action that may be deemed necessary, alongside allied nations, including possible participation in military action."

In Luxembourg, the European Union's 15 foreign ministers once again declared their support. In a joint statement, they said Mr. bin Laden and the Taliban "were now facing the consequences of their action."

Leaders in Hungary, Poland and Slovakia also expressed support.

But here and there, grumblings were beginning to be heard.

In France, the strongest criticism came from Noël Mamère, who is quite likely to be the Green Party candidate for the presidency next year.

"The military response launched by the Americans is an act of war against the Afghan people, a people who risk paying a high price for international terrorism," Mr. Mamère said.

The Communist Party, also a junior member of the Socialist coalition that runs the government, was equally critical. The head of the Communist Party, Robert Hue, said there were "serious doubts" that a military campaign could be "carried out without serious consequences for the people of Afghanistan."

"The form of the American intervention in Afghanistan, with what looks like massive bombardments, makes me worry that America has fallen into the trap set by bin laden and the Taliban."

In several European capitals, including Amsterdam, London, Paris, Madrid and Rome, hundreds of antiwar demonstrators have taken to the streets. In the Italian capital, one demonstration began on Sunday night around the Piazza Venezia and headed toward the American Embassy on the Via Veneto. The police stopped it before it arrived at the embassy.

In Berlin, some 2,000 demonstrators marched near the American Embassy chanting, "Achieve peace without weapons," and carrying banners saying, "War does not avenge the dead, it causes them."

In Greece, demonstrations against military intervention were much larger. Thousands of leftists, some of whom shouted, "American murderers!" were on the streets of Athens today.