Prime Minister Paul Martin on Saturday agreed to support a proposal that would keep suspects accused of gun violence in jail.

Martin will support "reverse onus" bail conditions, which means people accused of gun crimes must prove why they should be released.

The pledge came during a Saturday phone call with Ontario Premier Dalton McGuinty and Toronto Mayor David Miller.

Last week, McGuinty sent a letter to federal leaders asking them to support "reverse onus" bail conditions and other changes to the Criminal Code.

Martin's pledge is part of a multi-level government plan to crack down on gun crime, said Martin's spokesperson, Scott Reid.

The prime minister also supports increased mandatory minimum jail sentences for gun crimes, said Reid.

The move comes days after a 15-year-old Toronto girl was shot and killed in a gun battle on a downtown street crowded with Boxing Day shoppers. Six others were injured in the Yonge St. shootout.

Earlier in the campaign, Martin promised to ban all handguns, offering narrowly defined exemptions for target shooters. Collectors would be given five years to surrender their weapons.

With gunfire responsible for more than 50 of Toronto's 78 homicides this year, gun violence has become a key campaign issue in vote-rich Ontario.