President Bush today announced an increase in U.S. forces in Afghanistan "for the foreseeable future" to help confront a resurgent Taliban, and he urged European allies to lift restrictions that currently confine some of their NATO troops to secure areas of the country.

In a speech to a gathering of the American Enterprise Institute, a conservative think tank in Washington, Bush hailed "remarkable progress" in Afghanistan since U.S.-backed Afghan forces drove the radical Islamic Taliban movement from power in November 2001 and ended the country's role as a government-sanctioned safe haven for the al-Qaeda terrorist network.

But he acknowledged that the Taliban has made something of a comeback since then, thanks in part to profits from a surge in the cultivation of opium poppies.

With the Taliban reportedly gearing up for a spring offensive against the government of President Hamid Karzai, Bush said, he is asking Congress for $11.8 billion over the next two years "to help this young democracy survive" and has "ordered an increase in U.S. forces in Afghanistan."

Bush said he has extended for four months the stay of 3,200 U.S. troops now in Afghanistan and will "deploy a replacement force that will sustain this increase for the foreseeable future."

The troops that are being extended belong to the 3rd Brigade Combat Team of the Army's 10th Mountain Division. When their tour expires in the spring, the Army's 173rd Airborne Brigade based in Vicenza, Italy, will deploy to Afghanistan to replace them. The 173rd previously had been scheduled to go to Iraq.

Because another brigade had already arrived in Afghanistan to take over from the 10th Mountain Division unit, the extension of those troops and the deployment of the 173rd effectively double the number of U.S. combat brigades in the country.

Bush told the AEI, "The snow is going to melt in the Hindu Kush mountains. And when it does, we can expect fierce fighting to continue. Taliban and al-Qaeda are preparing to launch new attacks. Our strategy is not to be on the defense but to go on the offense. This spring, there's going to be a new offensive in Afghanistan, and it's going to be a NATO offensive, and that's part of our strategy. Relentless in our pressure, we will not give in to murderers and extremists."

But he added, "For NATO to succeed, member nations must provide commanders on the ground with the troops and the equipment they need to do their jobs." In addition, "allies must make sure that we fill the security gaps," he said.

"In other words, when there is a need, when our commanders on the ground say to our respective countries we need additional help, our NATO countries must provide it in order to be successful in this mission. As well, allies must lift restrictions on the forces they do provide so NATO commanders have the flexibility they need to defeat the enemy wherever the enemy may make a stand."

So far, troops from the United States, Canada, Britain and the Netherlands have borne the brunt of the fighting against the resurgent Taliban. U.S. commanders have urged other members of the 26-nation NATO alliance to contribute more forces to that effort, but some countries, such as Germany and France, do not allow their soldiers to deploy in parts of southern and eastern Afghanistan where the Taliban insurgency is strongest.

"Success in Afghanistan is important for our security," Bush said in today's speech. "We are engaged in a long ideological struggle between the forces of moderation and liberty versus the forces of destruction and extremism. And a victory for the forces of liberty in Afghanistan will be a resounding defeat in this ideological struggle. It's in our national interest that we succeed, that we help President Karzai and the people of Afghanistan succeed."

The International Security Assistance Force, as the NATO mission in Afghanistan is known, currently puts its strength at nearly 35,500 troops drawn from 37 nations, including small contingents from several non-members of the alliance. The force is commanded by a U.S. general and includes 14,000 American troops. An additional 12,000 U.S. troops are deployed in Afghanistan under separate command to conduct counterinsurgency operations and training.

In praising what he termed "real progress" in Afghanistan since the Taliban's rule ended, Bush said the Afghan economy has doubled in size in the past five years, the number of children in school has increased from 900,000 to more than 5 million, access to health care has grown markedly and more than 4.6 million refugees have gone home. Whereas women were barred from public office under the Taliban and girls were prohibited from attending school, Bush said, Afghanistan's parliament today includes 91 women, Karzai has appointed the first woman provincial governor, and about 1.8 million of the nation's school children are girls.

But in 2006, he said, "this enemy struck back with a vengeance." The number of roadside bombs across Afghanistan nearly doubled, direct-fire attacks on international forces almost tripled, and suicide bombings grew nearly fivefold, Bush said.

"These escalating attacks were part of a Taliban offensive that made 2006 the most violent year in Afghanistan since the liberation of the country," he said.

Bush decided to send more troops following what he said was a recently completed "top-to-bottom review of our strategy" in Afghanistan. In addition to beefing up its forces, he said, the United States will help the Afghan government increase the size of its national police from 61,000 to 82,000 by the end of 2008 and boost the ranks of its army from 32,000 to 70,000 over the same period. The increase will include commando battalions, a helicopter unit and combat support units, he said.

Bush also appealed to the American people and Congress to show "patience" and to support the mission of U.S. troops in Iraq. He obliquely criticized Democrats and some Republicans in the House for backing a resolution that expresses disapproval of his plan to send 21,500 additional U.S. troops to Iraq to help secure Baghdad and reinforce Anbar province in western Iraq.

Three weeks ago, he noted, the Senate unanimously confirmed his nomination of Army Gen. David H. Petraeus to take over command of U.S. forces in Iraq.

"Now, the House is debating a resolution that disapproves of our new strategy," he said. "This may become the first time in the history of the United States Congress that it has voted to send a new commander into battle and then voted to oppose his plan that is necessary to succeed in that battle."

While lawmakers "have every right to express their opinion," Bush said, "our men and women in uniform are counting on their elected leaders to provide them with the support they need to accomplish their mission." He said that "Republicans and Democrats have a responsibility to give our troops the resources they need to do their job and the flexibility they need to prevail."

In the House, meanwhile, debate on the resolution continued for a third day, with a vote planned for Friday. Yesterday, 11 GOP members broke ranks with the White House and took to the House floor to voice support for the resolution. Most, if not all, of the chamber's 233 Democrats are considered likely to vote for the resolution, as are 20 to 30 of the 201 Republicans.

"You know, one of the interesting things that I have found here in Washington is there is strong disagreement about what to do to succeed, but there is strong agreement that we should not fail," Bush said of the effort in Iraq.

"People understand the consequences of failure. If we were to leave this young democracy before the job is done, there would be chaos. And out of chaos would [come] vacuums, and into those power vacuums would flow extremists who would be emboldened, extremists who want to find safe haven."

Repeating a familiar warning, Bush said, "If we were to leave Iraq before the job is done, the enemy would follow us home."