Malala Yousafzai has returned to Pakistan for the first time since she was shot in the head by Taliban militants in 2012.
The Taliban targeted the then 15-year-old due to her advocacy of women's rights and the education of girls.
The Nobel Peace Prize winner arrived at Islamabad's Benazir Bhutto International Airport along with her parents, in the early hours of Thursday morning.
Tight security will accompany the Oxford University student's trip, details of which were kept secret prior to her arrival. When Ms Yousafzai left the airport, her vehicle was part of a convoy of 15, many of them occupied by heavily armed police.
Also on Thursday, the 20-year-old met with Pakistan's Prime Minister Shahid Khaqan Abbasi.
Due to the secrecy surrounding Ms Yousafzai's visit, it is not known how long she will remain in the country, and if she will visit her hometown in the Swat area of northeast Pakistan, and the site of the bus shooting.
As news broke about Ms Yousafzai's arrival in Pakistan's, residents welcomed her.
Cricketer turned opposition leader Imran Khan's party said Ms Yousafzai's return was a sign of the defeat of extremism in the country.
Mohammad Hassan, one of Ms Yousafzai's cousins, said her return to Pakistan was one of the happiest days of his life.
He continued that he did not know if his cousin would visit her home town, but said schoolchildren were jubilant on her return and hoped she would visit so that they could meet her.
Javeria Khan, a 12-year-old schoolgirl in Ms Yousafzai's hometown of Mingora, said she was excited about her return to the country: "I wish I could see her in Swat.
"I wish she had come here, but we welcome her."
Marvi Memon, a senior leader of the ruling Pakistan Muslim League party, also welcomed Ms Yousafzai, saying it was a pleasant surprise for her to see the student back home.
"What an incredible surprise I woke up to this morning" to know that Ms Yousafzai is back along with her parents, she said.
Ms Memon added it was a proud day for Pakistan that Ms Yousafzai was back in the country.
- On Pakistan Day on March 23, Ms Yousafzai tweeted her fondness for her home country
Prior to her shooting, Ms Yousafzai's career as an activist began in early 2009, when, aged just 11, she started writing a blog for the BBC about her life under Taliban occupation and promoting education for girls in Pakistan's Swat Valley.
She also featured in a documentary and soon began to gain prominence.
However, her campaign angered the Taliban for promoting "western ideals" and they staged the assassination attempt on her.
Following the attack, the 15-year-old was rushed to hospital and then later transferred to Birmingham's Queen Elizabeth Hospital.
Fearing reprisals in her native country, Ms Yousafzai and her family made Birmingham their home following her recovery.
In 2014 she became the youngest person to be awarded the Nobel Peace Prize and her campaign for children's rights to education across the world has seen her address the United Nations on the issue.