From the spectacular attack on Kunduz, in northern Afghanistan, to the assault on Tarin Kot in the south, here is a recap of Taliban offensives since September 2015:

- Kunduz assault -

On September 28, 2015, a stunning strike by vastly outnumbered Taliban fighters who infiltrated Kunduz allows them to quickly overrun the city.

The Taliban are driven out almost two weeks later by Afghan forces backed by US aircraft and NATO soldiers, but it marks the first time since 2001 that the Taliban take control of a major city in the country.

The operation also results in a disastrous strike on a Kunduz clinic run by the charity group Doctors Without Borders (MSF), that kills 42 people, of which 14 members of the NGO.

On October 3, US special forces coordinate a strike by an AC-130 gunship after mistaking the site for a Taliban headquarters. The raid lasts for almost an hour and leaves patients burning in their beds. MSF brands the strike a war crime.

- Southern districts under siege -

In December 2015, the Taliban break through the frontlines of Sangin -- a strategic opium-producing district in the southern Helmand province -- after days of pitched clashes with besieged Afghan forces.

In February and March 2016, Afghan forces -- stretched thin across multiple fronts -- withdraw from several southern districts in Helmand and Uruzgan without fighting. The government calls it a "strategic retreat" to reinforce other conflict zones.

- Spring offensive, Kabul targetted -

On March 5, 2016, the Taliban refuse to hold direct peace talks with the Afghan government, dealing a blow to international efforts to revive long-stalled negotiations aimed at ending the deadly 14-year insurgency.

In mid-April, the Taliban announce the start of their "spring offensive", dubbed "Operation Omari," after the mullah who founded the Taliban movement and whose death was announced in mid-2015.

The Taliban start out in Kunduz, but government forces, with the help of Western air power, manage to repel this latest offensive on the city.

Several days later, on April 19, a Taliban truck bomb and ensuing firefight kills at least 64 people and wounds some 350 others, in one of the deadliest assaults on the Afghan capital since the insurgents were toppled from power in 2001.

On May 21, Taliban supremo Mullah Akhtar Mansour is killed in a US drone attack in Pakistan. His successor Haibatullah Akhundzada calls on "American invaders" to leave Afghanistan.

- Taliban advances in the south -

In June US President Barack Obama announces that he is bolstering the US commitment in support of Afghan forces and authorising American forces to attack Taliban forces more head-on.

Under his decision the American forces can send their fighter jets in support of Afghan forces in combatting the Taliban. Military counsellors can also go nearer to combat zones.

A month later Obama announces that 8,400 US soldiers will stay in the country until 2017. Previously the number of US troops was to be reduced from 9,800 currently to 5,500 by the end of the year.

In early August, the Taliban begins a major offensive in Helmand, surrounding Lashkar Gah, a town of 200,000 inhabitants which is defended by the Afghan army, supported by American air strikes.

- Third provincial capital threatened -

The Taliban have now stormed into Tarin Kot, capital of the southern Uruzgan province, triggering pitched battles and urgent calls for reinforcements and air support.

The Taliban are still threatening Lashkar Gah and Kunduz.