Afghanistan’s President has again invited the Taliban to peace talks, calling it their “last chance” to give up their 16-year insurgency and join the political process.

Ashraf Ghani spoke at the opening of the so-called Kabul Process, a gathering of 23 nations, the EU, U.N. and NATO intended to discuss security and political issues in the country.

The Taliban has steadily expanded its reach since U.S. and NATO forces formally concluded their combat mission at the end of 2014 and transitioned to a support and counterterrorism role.

Past attempts at peace talks have failed. The Taliban have refused to negotiate with the government until all foreign forces leave, and still refer to themselves as a government in exile, angering authorities in Kabul.