TOKYO -- A Japanese journalist who returned from more than three years of captivity in Syria apologized Friday to the government and said he was kidnapped as soon as he crossed the border because of a "silly mistake" before he even started reporting.

Jumpei Yasuda faced a crowd of reporters in Tokyo for the first time since gaining freedom last week. He said he went to Syria on June 22, 2015, to see for himself the reality and how the conflict affected ordinary people, including women and children, as well as soldiers in areas controlled by anti-government groups. His plan was to follow up his earlier reporting in Syria.

Yasuda, a respected journalist known for his coverage of conflict zones, said he made a bad decision while crossing into Syria when his local escort suddenly changed plans and Yasuda followed a pair of unknown guides instead. As they walked into Syria, the pair grabbed him, pushed him into a car, took his luggage away and kept him in a house.

"It was an unthinkable silly mistake," he said, adding that he is fully accountable for his suffering.

"To everyone who assisted in securing my release and those who worried about me, I deeply apologize and would like to express my sincere appreciation," Yasuda, wearing a dark suit and tie, said as he bowed deeply. "I am also sorry that the Japanese government had to get involved because of me."

He was kidnapped by an al-Qaida branch known at the time as the Nusra Front, though the group never revealed its identity to him. A war monitoring group said Yasuda was recently held by a Syrian commander with the Turkistan Islamic Party, which mostly comprises Chinese jihadis in Syria. Yasuda said he was held earlier this year at a prison run by Uighurs who called themselves "Turkistans" -- one of several places he was moved to during his 40-month captivity. He believes he was mostly in Idlib in northwestern Syria.

Yasuda detailed his life in captivity during a more than 2 1/2-hour news conference. He said he was allowed to keep a diary -- one of his limited freedoms but a crucial record of his survival.

Nonetheless, his living conditions were harsh. He said he was harassed and tortured, even for making a noise. At a multistory facility, he was held in a solitary cell where he had to stay still within a tiny space. He had to keep his knees constantly bent and hardly had space to roll over while asleep. He said they punished him for creating noise, for example by turning off a fan in extreme summer heat. One of his captors told him the facility was in an area called Jabal Zawiyah.

Yasuda's release came suddenly. On Oct. 22, his captors said he was heading home, and the next day they drove him to a meeting point where they handed him over to Turkish authorities. They removed his blindfold as they arrived at the immigration centre in Antakya in southern Turkey. Yasuda said he didn't know how his release was won.

While the public generally welcomed Yasuda's safe return, some criticized him as a fearless troublemaker. In a country where those who act independently are often considered selfish and receive little sympathy when they fail after defying government-issued cautions, some people on Twitter demanded that Yasuda apologize for causing trouble. Past hostages have faced similar criticism upon returning home.

"I humbly accept criticisms and suggestions," Yasuda said. "Naturally, I receive the blame and attention because my actions caused trouble. But I hope people would take another step and think what is happening in Syria. And hopefully, the authorities would investigate my captors," he said. He also said the role of journalists in conflict zones is still crucial for the world to know the truth, and that he hopes his example can lead to a discussion of how safety and the quality of conflict zone reporting can be improved.

Rei Shiva, a journalist who has covered Iraq, Lebanon and other areas of the Middle East, said many reporters who cover conflict zones are not doing it just for money or fame, but want to see the situation themselves and tell the world about it. He said journalists who ignore government travel warnings become targets of bashing in Japan because many people are too unquestioning of government directives.

"Are we supposed to run away every time the government issues a travel advisory? Then there will be no way of knowing anything," Shiva said. "Because people in Japan don't feel strongly about their right to know, there is a lack of respect for journalists who fight for it."

Yasuda started reporting on the Middle East in the early 2000s and went to Afghanistan and Iraq. He was taken hostage in Iraq in 2004 with three other Japanese, but was freed after Islamic clerics negotiated his release. He worked as a cook in Iraq for nearly a year as part of his research for a 2010 book about labourers in war zones. He also wrote articles about his 2004 captivity.

Syria has been one of the most dangerous places for journalists since the conflict there began in March 2011, with dozens killed or kidnapped.

Asked if he will return to conflict zones after his suffering, Yasuda said his plans are still blank.