WASHINGTON — President Barack Obama asked Congress on Thursday for $83.4 billion for U.S. military and diplomatic operations in Iraq and Afghanistan, pressing for special troop funding that he opposed two years ago when he was senator and George W. Bush was president.

Obama’s request, including money to send thousands more troops to Afghanistan, would push the costs of the two wars to almost $1 trillion since the Sept. 11, 2001, terrorist attacks, according to the Congressional Research Service. The additional money would cover operations into the fall.

Obama is also requesting $350 million in new funding to upgrade security along the U.S.-Mexico border and to combat narcoterrorists, along with another $400 million in counterinsurgency aid to Pakistan.

“Nearly 95 percent of these funds will be used to support our men and women in uniform as they help the people of Iraq to take responsibility for their own future — and work to disrupt, dismantle and defeat al-Qaida in Pakistan and Afghanistan,” Obama wrote in a letter to House Speaker Nancy Pelosi, D-Calif.

Robert Gibbs, the White House press secretary, acknowledged that Obama has been critical of Bush’s use of similar special legislation to pay for the wars.

Last June, Congress approved $66 billion in advance 2009 funding for military operations. All told, the Pentagon would receive $142 billion in war funding for the budget year ending on Sept. 30.

The request is likely to win easy approval from the Democratic-controlled Congress, despite frustration among some liberals over the pace of troop withdrawals and Obama’s plans for a large residual force of up to 50,000 troops — about one-third of the force now there — who will train Iraqis, protect U.S. assets and personnel and conduct anti-terror operations.

The official request was sent early Thursday evening.

The request would fund an average force level in Iraq of 140,000 U.S. troops.

It would also finance Obama’s initiative to boost troop levels in Afghanistan to more than 60,000 from the current 39,000. And it would provide $2.2 billion to accelerate the Pentagon’s plans to increase the overall size of the U.S. military, including a 547,400-person active-duty Army.

Some Democrats were not pleased.

“This funding will do two things — it will prolong our occupation of Iraq through at least the end of 2011, and it will deepen and expand our military presence in Afghanistan indefinitely,” said anti-war Rep. Lynn Woolsey, D-Calif.

But House GOP leader John Boehner of Ohio predicted that Republicans would overwhelmingly support the request, provided congressional Democrats don’t seek to “micromanage” the war by adding a timeline or other restrictions on the ability of military officials to carry on the fight.

Defense Secretary Robert Gates, a holdover from the Bush administration, said, “The reality is the alternative to the supplemental is a sudden and precipitous withdrawal of the United States from both places, and I don’t know anybody who thinks that’s a good idea.” He said, “The reality is it would put everything we have achieved in Iraq at tremendous risk, and I believe it would greatly endanger our troops.”

Obama was a harsh critic of the Iraq war as a presidential candidate, a stance that attracted support from the Democratic Party’s liberal base and helped him secure his party’s nomination. He opposed an infusion of war funding in 2007 after Bush used a veto to force Congress to remove a withdrawal timeline from the $99 billion measure.

But he supported a war funding bill last year that also included about $25 billion for domestic programs. Obama also voted for war funding in 2006, before he announced his candidacy for president.

The request includes $75.8 billion for the military and more than $7 billion in foreign aid. Pakistan, a key ally in the fight against al-Qaida, will receive $400 million in aid to combat insurgents.

The upcoming debate in Congress is likely to provide an early test of Obama’s efforts to remake the Pentagon and its much-criticized weapons procurement system. He is requesting four F-22 fighter jets costing about $600 million as part of the war funding package but wants to shut the F-22 program down after that.

Included in the special measure is $400 million for the first installment of a new program to train and equip Pakistan’s military. The Associated Press reported last week that the program would total as much as $3 billion over the next five years and would include money for helicopters, night-vision goggles and communications equipment.

Distribution of the funding will be controlled by the military and will be tightly focused on improving the ability of Pakistan’s military, including its Frontier Corps, to better fight insurgents hiding in safe havens along the border. It also will allow commanders to provide humanitarian relief to people affected by military operations.

The funding measure would include $3.6 billion for the Afghanistan National Army.

Obama is also seeking $30 million in Justice Department funding to implement the shut down of the facility in Guantanamo Bay holding enemy combatants.

Poor countries would receive $448 million to help them deal with the global financial crisis.

The White House wants the bill for the president’s signature by Memorial Day, said a House Democratic aide.

Obama warned lawmakers not to succumb to the temptation to use the must-pass war funding bill as a vehicle for other spending.

“I want the Congress to send me a focused bill, and to do so quickly,” he wrote.

Obama announced plans in February to withdraw U.S. troops from Iraq on a 19-month timetable.

His new request would push the war and diplomatic money approved for 2009 to about $150 billion. The totals were $171 billion for 2007 and $188 billion for 2008, the year Bush increased the tempo of military operations in a generally successful effort to quell the Iraq insurgency.