OTTAWA -- Federal NDP Leader Jagmeet Singh is formally asking the prime minister to immediately give cities the leeway to ban handguns.

In a lengthy letter to Justin Trudeau outlining a long-term approach to tackling crime, Singh says more policing is not a solution to gun violence in cities because some measures, such as street checks and carding, have amplified distrust between police and racialized communities, Indigenous peoples and those struggling with mental illness.

Instead, he says allowing cities to ban handguns would help municipal authorities deal with the fact that many gun crimes are committed with legal guns.

"The federal government should not stand in the way of municipal leaders who know their communities best, and want to ban these weapons to keep their residents safe," he wrote.

Singh also wants the government to commit to spend $100 million a year, starting next year, on efforts to combat gang violence -- a target the Trudeau government has pledged to reach after 2022. He says this funding should focus on prevention, especially looking at youth gangs, bullying and cyberbullying.

He also wants more resources for the Canada Border Services Agency to curtail cross-border weapons smuggling.

In the wake of a deadly shooting in Toronto last month, the federal government has said it's considering ways to crack down on handguns and allow cities more flexibility in doing so.

Last week, Toronto city council passed a motion urging the federal government to forbid the sale of handguns in the city and for the province to outlaw the sale of handgun ammunition in the city.

Ottawa is considering this as one of several options to add to a slate of changes to federal firearms law introduced in legislation last year.

In his letter to Trudeau, Singh urges the prime minister to speak out more loudly against hate crimes and racist confrontations that have emerged "because of misinformed reactions to gun violence."

The root causes of violence -- such as poverty, racial discrimination, gaps in mental health services and a lack of affordable housing -- must also be addressed to reduce the prevalence of marginalized individuals and communities, he said.

"The primary reason I'm writing to you today is to ask for your commitment to develop long-term and effective solutions to the root causes of gun violence by partnering with the communities affected. That is the only way we can truly tackle the issue of gun violence."