WASHINGTON — The Trump administration is evaluating plans to send as many as 5,000 additional U.S. troops to Afghanistan, where America's longest war has hit a stalemate and local security forces have become overwhelmed by rising violence.

The Pentagon is considering options that include between 3,000 and 5,000 conventional military personnel to advise Afghan military and police units, those focused on fighting the Taliban, plus an unspecified number of additional special operations forces to escalate counter-terror operations against the al-Qaida and Islamic State loyalists entrenched along the Pakistan border. 

A U.S. defense official, speaking on the condition of anonymity, confirmed those plans to Military Times on Saturday. The 3,000 to 5,000 figures have been reported previously, by the Reuters news agency and The Washington Post.

U.S. Marines will return to Afghanistan's opium region

The United States announced it will send around 300 Marines back to Afghanistan. They will go to the opium-rich Helmand province to train local forces to fight the Taliban. The Marines should begin deploying this year and will remain in the province for nine months. Helmand is the main source of Afghanistan's thriving opium trade, which is worth an estimated $4 billion a year. The Taliban controls 85 percent of the province, which means much of the opium profit funds its efforts. The U.S. and NATO formally ended their combat mission in Afghanistan at the end of 2014. However, thousands of troops remain in the country, where they assist and train Afghan forces and carry out counterterrorism operations.

The White House could reach its decision in coming weeks and announce any intended strategy shifts at the NATO security summit scheduled for May 25 in Brussels. President Trump has said he will attend those talks. A senior Afghan defense official, also speaking on the condition of anonymity, told Military Times that NATO is looking at deploying up to 13,000 troops in all — a figure that would include a combination of U.S. and allied personnel.

Such an increase, while significant, is unlikely to bring a full-scale return to the gritty rural and urban fighting that U.S. and NATO troops encountered in Afghanistan prior to 2014, when President Barack Obama, eager to curtail America's involvement in the war, declared an end to combat there. Rather, it's likely to result in accelerated training for the Afghan army and police and a more aggressive effort to reverse the Taliban's momentum in several population centers.

U.S. officials in Kabul will say only that Army Gen. John Nicholson, the top commander there, has submitted his recommendation for a troop increase of a "few thousand" to bolster the U.S. military's train and advise mission.

"Those troops would be used to [train, advise, assist] below the corps level for the Afghan National Army and below the zone level for the Afghan National Police," said Capt. William Salvin, a U.S. military spokesman in the Afghan capital.

The Afghan army is divided into six corps. There are eight Afghan police zones.

During his congressional testimony in February, Nicholson highlighted his desire to push American and NATO advisers below the corps level and, thus, closer to the fight. He described the notional successes of a newly implemented "expeditionary advising package," a program that came to fruition after Obama last June granted new authorities to support the local security forces in their efforts to repel the Taliban and the estimated 20 terror groups who operate inside Afghanistan.

Nicholson also hopes to grow Afghanistan's special forces. With 17,000 commandos, these units have spearheaded operations across the country and have conducted nearly 70 percent of the country’s offensive operations. They are now capable of performing approximately 80 percent of their operations independent of U.S. advisers, Nicholson told lawmakers in February.

That work remains exceedingly dangerous. Two Army Rangers were killed this week, possibly by friendly fire, during a raid on an Islamic State headquarters in Achin, an endlessly violent district along the Pakistan border. A third soldier was killed there earlier this month.

Nicholson's recommendation follows stops in Kabul by two key administration figures, National Security Advisor H.R. McMaster and Defense Secretary Jim Mattis. They made separate visits to the war-torn region within a week of one another in April.

As the Trump administration weighs its options, 300 Marines composing Task Force South West have arrived in the ever-dangerous Helmand Valley to assist Afghan forces in retaking territory lost to the Taliban. Their arrival this month marks the first significant Marine presence there since 2014.

And on Friday, the Taliban announced the start of its annual spring offensive. The group's leaders have dubbed it Operation Mansouri, named in honor of their former supreme leader who was killed by a U.S. drone strike in Pakistan last May.

Shawn Snow is a Military Times staff writer and Early Bird Brief editor. On Twitter: @SnowSox184.

Andrew deGrandpre is Military Times' senior editor and Pentagon bureau chief. On Twitter: @adegrandpre.