US soldiers from the Marine Corps have returned to Afghanistan's Helmand province nearly three years after the US-led NATO forces ended combat mission in the country.

Commander of US and NATO forces in Afghanistan General John Nicholson attended a handover ceremony on Saturday marking the return of the elite force, the first American soldiers to be deployed in Afghanistan since 2014, an AFP news agency photographer said.

Part of a troop rotation, they will arrive in stages, eventually numbering some 300 who will take part in NATO's train, assist and advise mission.

 This is Taliban Country

The deployment to Helmand came a day after a resurgent Taliban announced the launch of their so-called Spring Offensive.

The decision to boost forces was first announced in January after Donald Trump took over as the new president of the US. He is seeking to craft a new strategy in Afghanistan.

Earlier this months, the US dropped the "mother of all bombs" in the Achin district of Nangarhar province, close to the border with Pakistan.

The Pentagon said it targeted a series of caves and bunkers used by the Islamic State of Iraq and Syria (ISIL) group, whose influence has grown in recent years.

Trump has criticised his predecessor Barack Obama's Afghanistan policy.

Helmand for years was the centrepiece of the US and British military intervention in Afghanistan.

The Taliban effectively controls or contests 10 of Helmand's 14 districts, aided by a huge opium harvest.

Civilians displaced

About 30,000 people fled fighting in the province last year, mostly fleeing to provincial capital Lashkar Gah, with the city at times practically besieged.

The roads from neighbouring districts are heavily mined by the Taliban.

The US has about 8,400 troops in Afghanistan with about another 5,000 from NATO allies.

Nicholson has called for a few thousand more to help break the stalemate against the fighters.

 Afghanistan: Taliban At The Gates

James Mattis, the US defence secretary, gave warning of "another tough year" in Afghanistan when he visited Kabul this week as part of consultations on the Trump administration's review of Afghan policy.

Most US forces in Afghanistan are taking part in NATO's training mission, seeking to boost Afghan forces who have been straining to beat back the Taliban since international forces ended their combat mission in 2014.

Afghanistan has seen intensified Taliban attacks across the country, leaving Afghan forces - already beset by killings, desertions, and vacuums in leadership and morale - stretched on multiple fronts.

They have faced high casualties, up 35 percent in 2016 with 6,800 soldiers and police killed, according to a US watchdog.

Last week the Taliban delivered a painful blow, with its fighters dressed in Afghan army uniforms killing at least 135 young recruits at a base near northern Mazar-i-Sharif city, according to official figures - though multiple sources have said the death toll is much higher.

The attack is believed to be the deadliest by the Taliban on a military target since they were driven from power in 2001. The group threatened more in the statement announcing their Spring Offensive on Friday.

Source: AFP news agency