By Mark Lander and Helen Cooper    February 1, 2016

President Obama plans to substantially increase the deployment of heavy weapons, armored vehicles and other equipment to NATO countries in Central and Eastern Europe, a move that administration officials said was aimed at deterring Russia from further aggression in the region.

The White House plans to pay for the additional weapons and equipment with a budget request of more than $3.4 billion for military spending in Europe in 2017, several officials said Monday, more than quadrupling the current budget of $789 million. The weapons and equipment will be used by American and NATO forces, ensuring that the alliance can maintain a full armored combat brigade in the region at all times.

Though Russia’s military activity has quieted in eastern Ukraine in recent months, Moscow continues to maintain a presence there, working with pro-Russian local forces. Administration officials said the additional NATO forces were calculated to send a signal to President Vladimir V. Putin that the West remained deeply suspicious of his motives in the region.

“This is not a response to something that happened last Tuesday,” a senior administration official said. “This is a longer-term response to a changed security environment in Europe. This reflects a new situation, where Russia has become a more difficult actor.”

It is not clear how Russia will react to the fortified military presence along NATO’s eastern flank. Since the signing of a cease-fire agreement last year, Mr. Putin’s government has tried to ease tensions with the West. Officials said the Russian government was eager for the United States and Europe to roll back economic sanctions, which suggested that it would not escalate tensions over the new military commitments.

But outside analysts were surprised by the magnitude of the increase in military funding for Europe, which is part of an overall budget request of $580 billion for the Pentagon. Mr. Obama, according to a defense official, is also going to ask Congress for a 35 percent increase — $7 billion — to fight Islamic State militants.

Some analysts said the increased funding and deployments would certainly rattle Russia. Among the countries where the equipment and additional forces could be deployed are Hungary, Romania and the Baltic countries, Pentagon officials said.

“This is a really big deal, and the Russians are going to have a cow,” said Evelyn N. Farkas, who until October was the Pentagon’s top policy official on Russia and Ukraine. “It’s a huge sign of commitment to deterring Russia, and to strengthening our alliance and our partnership with countries like Ukraine, Moldova and Georgia.”

While the increase in funding for Europe is significant, the administration is proposing that the money come from a separate war-funding account that is meant to pay for operations in the conflicts in Iraq and Syria, as well as the continued American military presence in Afghanistan. That means it is a one-time request, not necessarily a continuing commitment built in to budget requests beyond 2017, officials said.

“It’s a way to get around the budget caps” imposed on the Pentagon, said Todd Harrison, director of defense budget analysis at the Center for Strategic and International Studies in Washington.

But, Mr. Harrison added, the budget workaround may not succeed in reassuring fretful Eastern European allies because it leaves the decision on what do about future military spending in Europe for the next administration.

“If you want to be reassuring to our allies in Europe,” he said, “you’ve got to show you’ve got a future plan.”

Administration officials said the new investments were not just about deterring Russia. The weapons and equipment could also be deployed along NATO’s southern flank, where they could help in the fight against the Islamic State or in dealing with the influx of migrants from Syria.

“Initially, we were focusing on reassurance,” said one of the senior officials, who, like the others, spoke on the condition of anonymity to discuss internal military planning. “But while that was happening, we were stepping back and asking how to address the changed environment in a more programmatic and consistent way.”

Still, there is no doubt the primary target of the funding is Russia. Administration officials said that two years after its annexation of Crimea — an annexation that neither the United States nor its European allies recognize — it was imperative to send Moscow a message that NATO will do all it needs to do in order to stand behind Eastern European members worried that they could be next.

Russia has invested heavily in its military, transforming a cumbersome, Soviet-style army into a lighter, more flexible force, with the ability to carry out rapid interventions. That, combined with Mr. Putin’s willingness to use the military to expand Russia’s influence outside its borders, necessitated a stronger deterrent force, officials said.

“Applying this budget to Europe fulfills promises we’ve made to NATO on the collective defense of the alliance,” a senior defense official said Monday. “But it also shows our commitment and resolve to individual countries to which we will be putting a persistent rotational presence of forces to demonstrate our resolve in their, and our, collective defenses.”

He spoke on the condition of anonymity because he was not authorized to speak publicly about the budget.

The official said the Pentagon wanted a “heel to toe” rotational troop presence in Eastern Europe, meaning that there would always be the equivalent of a brigade in the region. Under a 1997 agreement known as the NATO-Russia Founding Act, both sides pledged not to station large numbers of troops along their respective borders.

Administration officials said they were confident that the new deployments would not be seen as breaching that agreement. In any event, Poland and the Baltic States argue that Russia’s incursion in Ukraine was a clear violation of the act, and that NATO should no longer abide by it.

Gen. Joseph F. Dunford Jr., the head of the Joint Chiefs of Staff, was in Brussels two weeks ago at a NATO defense meeting, where Eastern European countries again expressed concerns about Russia. In particular, representatives from the Baltic nations — Estonia, Latvia and Lithuania — have been asking for a big statement of American military support, officials said.

“This is a message that we see what they’re capable of, and what their political leadership is willing to do,” said another senior administration official, in a reference to Russia.

Eric Schmitt contributed reporting.