Afghan soldiers, Helmand province
© Noor Mohammad / AFP
A number of Afghan security forces servicemen have been killed in a US airstrike in Afghanistan, according to a statement issued by the US military.

The friendly-fire incident occurred in Afghanistan's Helmand Province late on Friday afternoon, the US military said in a statement.

"During a US supported ANDSF [Afghan National Defense and Security Forces] operation, aerial fires resulted in the deaths of the friendly Afghan forces who were gathered in a compound," the statement reads.

The US military has notified the Afghan authorities and launched an investigation to "determine the specific circumstances that led to this incident."

No information on the specific number of casualties resulting from the airstrike was immediately released.

The US and coalition forces have recently intensified their air operations in the country, dropping more munitions during the first half of 2017 than in all of the previous year.

In 2017, 1,634 munitions have been released in more than 2,000 combat sorties so far, according to figures disclosed by the US Air Force. Levels of military activity have reached those of the first half of 2012, which was the most "prolific" year for the US and its allies in Afghanistan.

The surge in airstrikes coincides with a spike in civilian casualties, according to the UN. Some 232 civilians have been killed in airstrikes so far this year, compared to the 162 in the same period in 2016. Roughly half of the civilian casualties were inflicted by the Afghan Air Force.

Intensified fighting has apparently led to a rise in friendly fire incidents, affecting both coalition and local Afghan forces. Last month, three Border Police agents were killed when a US military aircraft "returned fire" during a joint operation by Afghan and American special forces. In April, two US servicemen were killed in a suspected friendly fire incident. The military was not able to immediately determine whether the firing was initiated by US or Afghani forces and launched an investigation into the incident.