MOSCOW (Reuters) – The Taliban on Friday pushed back against major regional players at a conference in Moscow who said Afghanistan should not return to being an Islamic emirate, and it warned the United States against keeping troops in Afghanistan beyond their agreed withdrawal date.

At a summit in Moscow on Thursday, six weeks ahead of a deadline set last year for the withdrawal of U.S. troops, the United States, Russia, China and Pakistan called on the warring Afghan sides to agree on an immediate ceasefire.

In a joint statement they added that they “did not support the restoration of the Islamic Emirate.”

But Taliban political spokesman Mohammad Naeem, speaking to media in Moscow on Friday, said that it was up to the Afghan sides to decide their system of governance and that it should be an Islamic system.

“What is stated in the declaration is against all principles and is not acceptable,” he said.

A member of the Taliban’s political office, Suhail Shaheen, said negotiations should be sped up and said Washington should not keep troops in the country beyond their agreed withdrawal date.

“After that, it will be a violation of the agreement. That violation will not be from our side but it will be from their side. So in that case if there is action, of course, there will be reaction,” he said.

The Moscow conference aimed to shake up the largely stalled negotiations which have been held between the Afghan government and the Taliban in Qatar’s capital Doha.

“We expressed our readiness to accelerate the (peace) process,” Abdullah Abdullah, chairman of Afghanistan’s High Council for National Reconciliation, told Russia’s RIA news agency.

The conference will be followed by another summit in Turkey next month.

“We encouraged delegations representing the Islamic Republic and the Taliban…to prepare for and attend a leaders’ meeting in Istanbul in early April, the next critical milestone in the peace process,” U.S. Special Envoy Zalmay Khalilzad wrote on Twitter, adding that Thursday’s meeting had been “productive diplomacy.”

The Moscow conference was the first time the United States had sent a senior representative to talks on Afghanistan under a format launched by Russia in 2017.

Washington agreed last year with the Taliban to withdraw its troops by May 1 after nearly two decades, but President Joe Biden’s administration is reviewing its plans for Afghanistan and says all options remain on the table.

(Reporting by Maria Kiselyova, Andrew Osborn and Hameed Farzad; Writing by Gabrielle Tétrault-Farber and Charlotte Greenfield; Editing by Tom Balmforth, Peter Graff and Raissa Kasolowsky)