There is a massive manhunt underway after a man was shot dead during a funeral service for a murder victim in Toronto's west end.

Just after the noon hour on Friday, 18-year-old Amon Beckles was on his way to smoke a cigarette outside a Seventh Day Adventist Church in Etobicoke.

He was confronted by at least three men in the church lobby. One of them, allegedly brandishing a semi-automatic weapon, opened fire on Beckles. He was taken from the church to a nearby hospital, but did not survive his injuries.

In a sad connection, Beckles was cut down during a funeral for his friend -- 17-year-old Jamal Michael Hemmings, who was shot Nov. 9 in an Eglinton Avenue West parking lot. Beckles was a witness to Hemmings' murder.

Inside the sanctuary, 300 people were sent running and ducking for cover as the shots rang out.

A hunt for at least three suspects who fled the scene on foot was immediately started by police. The shooters are described only as wearing dark clothing and carrying semi-automatic weapons. They are believed by police to be the same men responsible for shooting Hemmings.

Police say they had no reason to expect violence during the funeral. If police had, said Chief Bill Blair, officers would have been present.

Blair called the shooting "appalling" during an afternoon news conference.

"The public nature of this violence demonstrates the callousness … some of these gang members have and the total disrespect they have for their community and for public institutions, like churches," said Blair. He added that he thinks the shooters' conduct is "shocking and surprising to us all."

Blair said that after this summer of violence he finds himself less and less surprised at the levels to which some gang members will descend. He also called for witnesses to come forward with information.

Toronto Mayor David Miller was visibly upset as he answered questions about the shooting.

"This is a church and people went there to mourn … and the kind of despicable thugs that would go when people are mourning and do this don't belong on the streets -- they belong in jail," said Miller.

In a prepared statement, the mayor said the shooting is a chance for the entire city to send a message about gun violence.

"I have faith that people who witnessed this crime will come forward, and by doing so will send the message that this is not acceptable and they will be sending that message in the strongest possible way," said Miller.

The pastor of the Etobicoke church where the shooting occurred also expressed his dismay at the callous nature of the attack.

"If you can come into the house of the Lord, a sacred place, and do something like that, I wonder what influences are influencing their life," said Reverend Andrew King.

Toronto is experiencing a record-high number of gun-related murders this year. Of the 69 homicides in the city, 48 so far have involved guns.

The latest shooting happened during a city-wide gun amnesty, in which people are encouraged to turn-in illegal weapons without fear of prosecution.