COLOMBO, Sri Lanka -- A Sri Lankan man who went on a knife rampage in a New Zealand mall was "brainwashed" by neighbours from the Middle East, his mother said Saturday.

Ismail Fareeda spoke to a local TV channel about her son as the Sri Lankan government promised to work with New Zealand authorities to investigate Friday's attack. Ahamed Adil Mohamed Samsudeen, who was shot dead by police after stabbing seven people, had been on a terror watchlist and was under surveillance. New Zealand authorities said he had been inspired by the Islamic State jihadist group.

Samsudeen's mother accused neighbours she said were from Syria and Iraq of radicalising her son in an interview with the Hiru TV network from her home in Kattankudy, 330 kilometres (206 miles) east of Colombo.

She said Samsudeen was injured in a fall in 2016 and that the neighbours, whom she did not name, seized the opportunity to influence him, adding they "were the only people who helped him as he recovered".

"Those neighbours from Syria and Iraq are the ones who brainwashed him," she said, adding her son had started posting radical views on social media after meeting the neighbours.

"We knew there was a change in him. The change came after he left the country" and settled in New Zealand in 2011, she said.

She added her two other sons had reprimanded the 32-year-old over his radical views.

- Brother questioned -

Sri Lankan police said Samsudeen was born in Kattankudy and brought up in Colombo where he went to a Hindu secondary school and studied maths and computer science.

His father is a retired school principal currently in Toronto, Canada.

Kattankudy is a majority Muslim town in eastern Sri Lanka. It was also the home of some of the attackers who staged suicide bombings in Colombo on Easter Sunday in 2019. Authorities were investigating if Samsudeen had any links with those who killed 279 people in the attacks on three churches and three hotels.

The 2019 bombings were blamed on a group that pledged allegiance to the then-Islamic State leader Abu Bakr al-Baghdadi. The government said it would work with New Zealand over the case.

"Sri Lanka condemns this senseless violence, and stands ready to cooperate with New Zealand authorities in any way necessary," foreign ministry spokesman Kohularangan Ratnasingam said in the government's first comment on the incident.

Ratnasingam commended the quick response by New Zealand police in dealing with the attacker.

Sri Lankan police sources said criminal investigators had interviewed the attacker's brother, who lives in Colombo.

"We are collecting information about him as well as anyone else who may have had contacts with him," a top police official said.

Sri Lanka's Muslim Council has condemned the Auckland attack as a "barbaric act of terrorism".

"This reminds all of us to come together and be united and fight against terrorism and violent extremism locally and internationally for the betterment of everybody," council member Mohamed Hisham told AFP.

Sri Lankan Muslim legislator Mujibur Rahman said his community was saddened by the attack, while lauding New Zealand Prime Minister Jacinda Ardern for easing public sentiment.

"Her statement soon after the incident defused the situation and ensured there was no harm to the Sri Lankan community (in New Zealand)," Rahman told AFP.

Ardern insisted no one community should be singled out for the violence.

"It was carried out by an individual, not a faith, not a culture, not an ethnicity," Ardern said.