What remains of al-Qaeda in Afghanistan is now working more closely with the Taliban, a spokesman for the U.S. led-mission there told reporters Thursday. If true, the renewed cooperation between the two groups marks another chapter in a relationship that has ebbed and flowed since 2001.

According to U.S. Army Brig. Gen. Charles Cleveland, al-Qaeda is providing more “capabilities and skills” to the 30,000 strong insurgent group than they have in the past.

Last year, Ayman al-Zawahiri, the leader of al-Qaeda, announced his support for the Taliban’s new head, Mullah Akhtar Mohammad Mansour.

“Since that time, we have seen more interaction. We have seen them working more together,” Cleveland said.

Mansour’s ascension to power was tumultuous, as the insurgent group was rocked when it was discovered that its senior leadership had been hiding the death of Mullah Omar, the Taliban’s shadowy leader, for more than two years.

Cleveland did not specify what type of skills al-Qaeda is providing to the Taliban; in the past, the terror group has provided bomb-makers and suicide bombers to its allies. According to Cleveland, there are roughly 300 al-Qaeda fighters still in Afghanistan spread out across a number of provinces such as Kunar, Kandahar and Ghazni.

“Although [al-Qaeda] have been significantly diminished, they do have the ability to regenerate very quickly, and they still do have the ability to pose a threat,” Cleveland said.

Al-Qaeda in the months before 9/11 had roughly 3,000 fighters loyal to its then-leader, Osama bin Laden. In the 15 years since the terror attacks, the United States has systematically gone after the group and its various global offshoots, killing its leaders with drone strikes and Special Operations raids.

The United States has roughly 10,000 troops still in Afghanistan providing advice and assistance to the embattled Afghan security forces. While the United States announced an official end to its combat role there in 2014, U.S. and allied Special Operations forces often accompany their Afghan counterparts on missions against the Taliban. In addition to the United States’ advisory role, known as Resolute Support, U.S. forces also run a counter-terrorism campaign that specifically goes after al-Qaeda as well as the Islamic State’s franchise based out of Nangarhar Province in the east of the country.

According to Cleveland, there are roughly 1,500 Islamic State fighters in Afghanistan, a number, he believes, that has been whittled down because of U.S. airstrikes. Since January  the United States has conducted roughly 120 airstrikes against terrorist targets in Afghanistan, the majority of which were aimed at the Islamic State. Under current rules of engagement, U.S. aircraft can only strike the Taliban in situations that involve the defense of U.S. forces or if both U.S. and Afghan troops are directly threatened.

Gen. John F. Campbell, the former commander of U.S. forces in Afghanistan, recommended resuming offensive airstrikes against the Taliban prior to the end of his tenure earlier this year. His replacement, Gen. John W. “Mick” Nicholson Jr. is in the midst of a 90-day assessment of the situation in Afghanistan, and it is unclear if he will make a similar recommendation to the president. He is expected to report this month.

The Taliban made significant gains in 2015, and at one point took control of the northern city of Kunduz before being pushed out by Afghan and U.S. forces supported by airstrikes. The offensive marked the first time the Taliban had control of an urban area since the group was first routed in 2001.

The Taliban controls large swaths of rural territory, including in its birthplace of Helmand Province. According to Cleveland, fighting around Helmand has been especially light this past month as the Taliban has been concentrated on the annual harvest. The Afghan Army’s embattled 215th Corps has lost a number of villages in Helmand in recent months, and the funds acquired from the recent harvest will likely allow the Taliban to go on the offensive.

“We think that’ll be the next big Taliban push,” Cleveland said. “We think it will come in Helmand.”