By Leah Schnurr

OTTAWA (Reuters) - Hundreds of mourners attended the funeral of a mentally ill black man whose death after he was arrested by police in Canada's capital city sparked a debate about race in a country that prides itself on a reputation for being tolerant.

At least 600 people including Ottawa Mayor Jim Watson and other local politicians turned out on Friday for the Muslim funeral of Abdirahman Abdi, filling Ottawa's largest mosque and spilling onto the street.

Watson was criticized earlier in the week for not making a statement until two days after the arrest on Sunday.

Witnesses told local media that Abdi, 37, was beaten by police officers who responded to calls of a disturbance. A video taken by a bystander showed Abdi in a bloodied shirt lying face down on the ground with his hands cuffed behind him and his pants pulled down before paramedics arrived.

His death echoed events in the United States, where a string of police killings of black men and allegations of police brutality and racial bias have sparked protests. Some U.S. confrontations were also caught on video.

In a statement read at the funeral on behalf of the family, Abdi was remembered as a "wonderful son, amazing brother and kindhearted uncle."

His family said in the statement that Abdi was "such a kindhearted person, what happened to him that Sunday wasn't fair at all and shouldn't be justified by any means."

"We all have many questions but we are trying to be patient."

Ontario's Special Investigations Unit is investigating the circumstances surrounding Abdi's arrest. Some advocates have called for criminal charges to be filed.

There have also been calls for a probe into whether race was a factor as advocacy groups voiced concerns over police violence against minorities.

"People are very concerned and it's not only among minorities, it's across society at large," said Abdullah Hassem, 61, who attended the funeral. "We must respect law and order, but at the same time, law and order must respect the people."

Ottawa police Chief Charles Bordeleau, who did not attend the funeral, said on Friday that officers have been taunted and videotaped in "a number of incidents" after Abdi's death.

"People are reacting right now, but I think we need to take a step back," Bordeleau told an Ottawa radio station.

A march was planned in Ottawa for Saturday. Another was held in Montreal on Thursday.

(Additional reporting by Ethan Lou in Toronto, Editing by Jeffrey Hodgson)