WASHINGTON, March 7 (Xinhua) -- U.S. Secretary of State Antony Blinken proposed a United Nations-led peace conference on the Afghan issue in a recent letter to Afghan President Mohammad Ashraf Ghani, U.S. media reported on Sunday.

In a Feb. 28 letter to Ghani, Blinken proposed a UN-led peace conference in Turkey "to discuss a unified approach to supporting peace in Afghanistan," reported The New York Times that obtained a copy of the proposals.

Envoys from the United States, China, Russia, Pakistan, Iran and India would attend the proposed UN-led conference, according to the report.

The proposals included a road map for a future Afghan government with Afghan Taliban representation, a revised Afghan constitution, and terms for a permanent and comprehensive cease-fire.

Blinken noted in the letter that the United States had not decided to pull out the remaining about 2,500 troops from Afghanistan by May, but he expressed concern that "the Taliban could make rapid territorial gains" following a U.S. withdrawal.

The report said the existence of the letter, which was first reported by the TOLOnews channel in Afghanistan, was confirmed by a U.S. official in Washington and the Afghan government.

However, a spokesperson of the U.S. State Department on Sunday declined to comment on the letter. "We have not made any decisions about our force posture in Afghanistan after May 1. All options remain on the table," said the spokesperson.

The United States and the Afghan Taliban signed an agreement in late February 2020, which called for a full withdrawal of the U.S. military forces from Afghanistan by May 2021 if the Taliban meets the conditions of the deal, including severing ties with terrorist groups.

The administration of President Joe Biden had noted that the Taliban had not met its commitment under the U.S.-Taliban deal.

The war in Afghanistan, which has caused about 2,400 U.S. military deaths, is the longest one in U.S. history.