KABUL - Taliban's new chief told Kabul on Tuesday it must cancel a security deal with the United States and expel all foreign troops if it wants peace in Afghanistan.

Mullah Mansoor made the demand in his first message since taking charge of the militant group after the death of founding leader Mullah Omar was confirmed in July.

"If the Kabul administration wants to end the war and establish peace in the country, it is possible through ending the occupation and revoking all military and security treaties with the invaders," Mansoor said in a message posted in English on the Afghan Taliban's website.

Washington and Kabul signed a security deal in September last year allowing around 13,000 foreign troops - including 10,000 US - to stay on after NATO’s combat mission ended in December 2014.

"The Taliban believe if the country is not under occupation, the problem of the Afghans can be resolved through intra-Afghan understanding," Mansoor said.