From an article on the Washington Post titled "This is where American Special Operations forces are helping advise U.S allies". These are primarily Army Special Forces units in a training and advisory role.
U.S. Special Operations forces have been quietly deployed around the world since the Sept. 11, 2001, attacks in an effort to shore up U.S. allies embroiled in their own conflicts. While not secret, the missions — known often by some variation of “train, advise and assist” — have served as an extension of America’s larger wars in Afghanistan and Iraq. Instead of large deployments of troops, U.S. Special Operations forces instead embed with local militaries to help bolster their capabilities and often accompany them on missions that serve both their government’s interests and those of the United States.
Below is a list of countries where the Pentagon has acknowledged the presence of U.S.-led “advise, assist and accompany” missions in recent years and a brief description of operations in those countries. This list is not exhaustive.
Somalia and Kenya. Since December 2013, the United States has maintained a small contingent of U.S. troops in Somalia and Kenya to help advise local forces and to support the African Union Mission in Somalia (AMISOM), according to the U.S. Africa Command. AMISOM is composed of peacekeepers from a consortium of African countries, and they have have been targeted by al-Shabab, an al-Qaeda-aligned group operating predominantly in Somalia. U.S. Special Operations forces have conducted raids against al-Shabab, along with its Somali allies, and U.S. aircraft regularly carry out airstrikes in the region.
Uganda. After a 2012 campaign to stop Joseph Kony, the warlord and commander of the brutal Lord’s Resistance Army, the Pentagon deployed a detachment of U.S. Special Operations forces, including Army Green Berets, and drones to help local forces, including Ugandan troops, to locate Kony in the neighboring Central African Republic.
Tunisia. Little is publicly known about U.S. forces in Tunisia, other than that there is a small contingent of Special Operations forces there — probably from Marine Corps Forces Special Operations Command — helping its Tunisian counterparts to develop their ability to counter extremist groups within and near their borders.
Mauritania. While the United States gave Mauritania two advanced surveillance aircraft in 2014 to help counter al-Qaeda’s affiliate in the region, known as al-Qaeda in the Islamic Maghreb, little is known about the “train, advise and assist” mission there. It probably resembles U.S. involvement in other African countries: a small Special Operations detachment working with its local counterparts.
Niger. After the kidnapping of more than 200 schoolgirls by the militant group Boko Haram in nearby Nigeria in 2014, the United States deployed a small tranche of Special Operations forces to help build up the militaries of countries such as Niger, Nigeria and Chad. The United States and France also have flown drones out of Niger’s capital in an effort to gather intelligence on Boko Haram. U.S. and French forces cooperated across West Africa after France intervened in Mali in 2012, following a revolt there.
Mali. In 2013, a handful of U.S. Special Operations forces deployed to Mali to help assist French forces fighting there and coordinate military aircraft in the region. It is unclear whether U.S. forces are still in Mali; however, at least one Special Operations soldier was present in the country’s capital when al-Qaeda militants opened fire in a local hotel and took more than 130 people hostage in November 2015.
Philippines. The United States has helped train and assist Philippine forces since 2001. A continually rotating force of Special Operations troops has helped the Philippine government fight the Abu Sayyaf Group, an Islamist group. U.S. forces are barred from participating in direct combat; instead, they help Philippine troops locate Abu Sayyaf havens. U.S. forces have also conducted information campaigns and civil affairs projects to build local opposition to the group.
Colombia. There has been consistent U.S. involvement in Latin America since the start of the “War on Drugs” in the 1980s. Elements from the Joint Special Operations Command and the CIA both helped take down one of Colombia’s most notorious drug lords, Pablo Escobar, in the early 1990s. In recent years, Special Operations forces have helped the Colombian military with intelligence and advanced military equipment as it has fought FARC rebels. In late 2015, the Colombian government struck a cease-fire with the rebel group and it is unclear whether U.S. forces continue to aid Colombian troops.
U.S. Special Operations forces are also engaged on more traditional battlefields:
Iraq. American troops have been in Iraq since the 2003 invasion. Although the majority of U.S. troops pulled out in 2011, a small element of Special Operations forces advised some parts of the Iraqi military until the Islamic State overran the city of Mosul in the summer of 2014. Since then, the United States has pledged air support and a limited number of advisers to help the Iraqis fight the Islamic State. U.S. troops and U.S. Special Operations forces are training units from the Iraqi military and helping them call in airstrikes. The Pentagon has gone to great lengths to keep U.S. forces off the front lines; however, a Delta Force soldier accompanying Iraqi Kurds was killed on a raid in northern Iraq in 2015 and a U.S. Marine, stationed at an American fire base, died after coming under rocket fire last month.
Syria. In December, President Obama announced that a small contingent of U.S. Special Operations forces would enter Syria to help train, advise and assist Syrian forces known as the Syrian Democratic Forces and the Syrian Arab Coalition. Both are amorphous groups of “moderate” Syrian rebels and Syrian Kurds. While the White House said the contingent would only consist of 50 troops, it is unclear how many are there now. In February, U.S. Special Operations forces helped Syrian opposition forces retake the town of al-Shaddadi from the Islamic State in northeastern Syria.
Afghanistan. The United States’ first foray into Afghanistan in the weeks after the Sept. 11, 2001, attacks involved CIA paramilitary units and U.S. Special Operations forces, advising and assisting parts of the Northern Alliance, which was fighting the Taliban. As the war dragged on, U.S. forces continued to advise and assist the newly formed Afghan Security Forces and local police. Currently, roughly 9,000 U.S. troops remain in Afghanistan, following an end to U.S. combat operations in November 2014. The troops that remain are advising the Afghan military and its commandos. In the country’s restive south, a U.S. Green Beret was recently killed while accompanying his Afghan counterparts on a mission to help retake parts of the city of Marjah.