A senior Pakistani Taliban commander has written to Malala Yousafzai, the teenage education activist shot by militants, accusing her of "smearing" them and of promoting "satanic" values, while urging her to return home.

Gunmen from the Tehreek-e-Taliban Pakistan (TTP) shot Malala, now 16, in the head in her home town in Swat last October after she had campaigned for the right of girls to go to school.

She made a powerful speech to the UN on Friday in her first public appearance since the near-fatal attack, vowing to continue her struggle for education and not be silenced by the militants.

In an open letter released Wednesday, Adnan Rasheed, a former air force member turned TTP cadre, said he personally wished the attack had not happened, but accused her of running a "smearing campaign" against the militants.

"When you were attacked it was shocking for me," Rasheed wrote in English.

"I wished it would never happened (sic) and I had advised you before."

But he added: "Taliban believe that you were intentionally writing against them and running a smearing campaign to malign their efforts to establish Islamic system in Swat and your writings were provocative.

"... It is amazing that you are shouting for education, you and the UNO (UN) is pretending that you were shot due to education, although this is not the reason... not the education but your propaganda was the issue," he continued.

"What you are doing now, you are using your tongue on the behest of the others."

The letter was sent to reporters in northwest Pakistan and its authenticity confirmed to AFP by a senior Taliban cadre who is a close associate of Rasheed. It is understood Malala has not received the letter herself.

The claims of smearing the Taliban echoed the explanation the militants gave when they claimed responsibility for shooting Malala.

"She always speaks against us. We will target anyone who speaks against the Taliban," a TTP spokesman told AFP in October last year.

"We warned her several times to stop speaking against the Taliban."

Rasheed accused Malala of seeking to promote an education system begun by British colonialists to produce "Asians in blood but English in taste", and said students should study Islam and not the "satanic or secular curriculum".

"I advise you to come back home, adopt the Islamic and Pashtun culture, join any female Islamic madrassa near your home town, study and learn the book of Allah, use your pen for Islam and plight of Muslim ummah (community)," Rasheed wrote.

Malala was given life-saving treatment in Britain, where she now lives with her family.

Rasheed was sentenced to death over a 2003 attack on Pakistan's then military ruler Pervez Musharraf, but escaped from custody in a mass jailbreak in April last year.

He said he had originally wanted to write to Malala to warn her against criticising the Taliban when she rose to prominence with a blog for the BBC Urdu service chronicling life under the militants' 2007-09 rule in Swat, in northwest Pakistan.

The Taliban have destroyed hundreds of schools across the northwest, an area on the frontline of the country's bloody struggle against Islamist militants.

But Rasheed said the attacks were necessary because government forces used schools as hideouts and bases.

Gordon Brown, the former British prime minister turned UN special envoy for global education, who has supported Malala since she was shot, issued a caustic response to the Taliban letter.

"Nobody will believe a word the Taliban say about the right of girls like Malala to go to school until they stop burning down schools and stop massacring pupils," he said in a statement.

Last month, militants blew up a bus carrying female students in Pakistan's southwestern city of Quetta, and then stormed a hospital where survivors had been taken for treatment. At least 25 people were killed in the attacks.

Malala's brave fight back from her injuries and speech at the UN have made her a leading contender for the Nobel Peace Prize. But the response to her in Pakistan has been mixed.

Many have hailed her as a national heroine but others have criticised her for promoting a "Western" agenda.