WHITE HOUSE - Following an announcement by President Donald Trump declaring the United States' commitment to Afghanistan, Secretary of Defense James Mattis said Tuesday he has not yet made a decision on how many troops to send to the South Asian country.

Speaking from Baghdad, Mattis said he is consulting with Joseph Dunford, the chairman of the Joint Chiefs of Staff, and will make the decision based on his plan.

Mattis Ponders Afghan Troop Surge; Trump Speech Reaction Mixed

In an evening address from a military base outside Washington Monday, Trump said that he would not talk about numbers of troops or plans for further military activities, unveiling a "condition-based approach" to defeating terrorism in Afghanistan, without going into detail.

Mattis Ponders Afghan Troop Surge; Trump Speech Reaction Mixed

The president has approved up to 4,000 more U.S. troops in Afghanistan, according to sources, speaking on condition they not be named.

Mattis Ponders Afghan Troop Surge; Trump Speech Reaction Mixed

Currently, there are about 8,400 U.S. troops in Afghanistan. Most are advising Afghan forces, though some are tasked with carrying out counterterrorism operations against groups such as the Taliban or the Islamic State’s Afghan affiliate.

That number is down significantly from the height of former President Barack Obama’s troop surge, which saw nearly 100,000 U.S. troops in Afghanistan in August 2010.

After years of deriding the U.S. war in Afghanistan as a "complete waste," President Donald Trump on Monday explained why he now believes it is in the United States' interest to remain committed to the South Asian country.

His goal, he said, is to stop the re-emergence of safe havens for terrorists to threaten America and make sure they do not get their hands on nuclear weapons.

"Conditions on the ground, not arbitrary timetables will guide our strategy from now on. America’s enemies must never know our plans or believe they can wait us out. I will not say when we are going to attack, but attack we will," Trump told about 2,000 service members at Joint Base Myer-Henderson Hall.

Immediately following the president’s speech, Secretary of State Rex Tillerson released a statement saying: "We stand ready to support peace talks between the Afghan government and the Taliban without preconditions. We look to the international community, particularly Afghanistan’s neighbors, to join us in supporting an Afghan peace process."

Trump, in his address, however, very publicly and directly put Pakistan on notice.

"We have been paying Pakistan billions and billions of dollars at the same time they are housing the very terrorists they are fighting. But that will have to change and that will change immediately," Trump vowed.

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The president’s address received mixed initial reviews.

"The president failed to define the goals or objectives that would direct the actions of the whole of government approach. The only thing he demonstrated was that his original belief that you can rip troops out of a combat zone without considering the fallout of that action was, in fact, wrong," said Moira Whelan, a partner of BlueDot Strategies and former senior State Department official.

"Trump repealed his original Afghanistan position, but he failed to replace it with something that will make America safer," Whelan told VOA.

The conflict in Afghanistan – with a factionalized unity government riddled with systemic corruption -- has dragged on for 16 years, becoming the longest U.S. war ever, since the Sept. 11, 2001 al-Qaida attacks on the United States.

Expressing frustration, Trump informed Afghanistan that the commitment by the United States is not unlimited and America’s support not a blank check.

The American people, he warned, expect "to see real reforms and real results."

U.S. Vice President Mike Pence, at Trump's request, spoke to Afghanistan President Ashraf Ghani on Monday ahead of the address.

Tillerson had spoken over the phone with Pakistani Prime Minister Shahid Khaqan Abbasi, Indian Foreign Minister Sushma Swaraj and Afghan Foreign Minister Salahuddin Rabbani, according to the State Department, about how the United States would like to work with each country to stabilize South Asia through a new, integrated regional strategy.

U.S. generals advised Trump to send several thousand more troops to break the stalemate and retake territory from the Taliban, which controls nearly half the country. But Trump, who campaigned on an "America First" foreign policy, has been reluctant to commit more resources to the country.

Afghanistan president Ashraf Ghani expressed appreciation for Trump's decision Tuesday.