Nobel Peace Prize winner Malala Yousafzai broke down in tears during an emotional return to her native Pakistan on Thursday, six years after she was shot in the head by Taliban gunmen for advocating greater education of girls.

Yousafzai, travelling with her father and younger brother, met Prime Minister Shahid Khaqan Abbasi in the capital, Islamabad, before giving a brief speech on national television.

"It's the happiest day of my life. I still can't believe it's happening," she said, wiping away tears.

"I don't normally cry ... I'm still 20 years old but I've seen so many things in life," added Yousafzai, clad in a traditional shalwar khameez outfit with her head covered with a red-and-blue duppata scarf.

Yousafzai spoke of the importance of education and the efforts of her charitable foundation to help girls, often switching between English and the Pashto and Urdu languages.

"Welcome home," Abbasi told Yousafzai. "When she went away, she was a child.... She has returned as the most prominent citizen of Pakistan."

It was Yousafzai's first visit to her homeland since she was airlifted to Britain for medical treatment in 2012.

But she is unlikely to travel to her home region of Swat, in mountains northwest of Islamabad, due to security threats against her, a relative and security sources told Reuters.

"It's been a long-held desire of Malala Yousafzai and her parents to visit Swat and see her relatives and friends. But she was not given permission due to security concerns," said one relative, who declined to be identified.

Earlier, Pakistan's Geo TV showed footage of Yousafzai after she arrived at Islamabad airport, walking to a car escorted by security officials.

In October 2012, masked gunmen stopped a bus taking Malala and some friends home from school and shot her. Two of her friends were also wounded.

At the age of 17, in 2014, Yousafzai became the youngest recipient of the Nobel Peace Prize for her education advocacy. She also became a global symbol of the resilience of women in the face of repression.

Longing for her homeland

Last week on Twitter, Yousafzai expressed a longing for her homeland. She now lives in Great Britain.

"On this day, I cherish fond memories of home, of playing cricket on rooftops and singing the national anthem in school. Happy Pakistan Day!" she wrote on March 23.

Prime Minister Justin Trudeau and Yousafzai attend the World Economic Forum annual meeting in Switzerland in January. Though she's arguably the world's most well-known Pakistani, she is a polarizing figure in her home country. (Denis Balibouse/Reuters)

After surviving the attack, Yousafzai was airlifted abroad and underwent surgery.

The Pakistani Taliban, who seized control of her hometown in Pakistan's Swat Valley before being pushed out by the army in 2009, later claimed the attack in response to her blog for the BBC Urdu service advocating girls' education.

Girls' school built with Nobel prize money

The hardline Islamist movement blew up girls' schools and imposed a strict interpretation of Shariah law during their rule over Swat.

Unable to return to Pakistan after her recovery, Yousafzai moved to Britain, setting up the Malala Fund and supporting local education advocacy groups with a focus on Pakistan, Nigeria, Jordan, Syria and Kenya.

Earlier this month, a new girls' school built with her Nobel prize money opened in Shangla, near her home district of Swat.

During her trip to Pakistan, which is expected to last several days, Yousafzai is expected to stay in Islamabad and meet friends and family at a hotel in the capital, Geo reported.

Yousafzai is currently studying at Oxford University.

While she is arguably the most recognizable Pakistani in the world, Yousafzai — known almost universally as Malala — is a polarizing figure at home. She is frequently attacked by conservative Pakistanis as portraying her country in a bad light and seeking her own fame.