Rahm Emanuel, the mayor of Chicago who acted as White House chief of staff until 2010, is hoping to initiate a nationwide campaign of disinvestment from companies that make and sell military-style assault rifles along the lines of the 1980s disinvestment from apartheid South Africa.

Emanuel has instructed the fund managers of the city's pension reserves to find out how much of the holdings are invested with assault weapons manufacturers and sellers as a first step towards financial withdrawal. Semi-automatic rifles have become a focal point of the debate around gun control in the wake of the Newtown shooting, in which a Bushmaster AR-15 was deployed to kill 20 young school children and six of their teaching staff.

Announcing the move on Monday, Emanuel at first implied that he would encourage disinvestment of city retirement funds from all gun manufacturers and sellers, but later clarified that to refer specifically to those dealing in assault rifles.

It is not clear how substantial any disinvestment would be as the scale of Chicago's financial holdings in gun companies is not yet known. However, the mayor is clearly hoping that the city will act as an incubator of similar actions across the US.

Amer Ahmad, the city comptroller, told the Chicago Tribune that the mayor was modelling his plan on the anti-apartheid disinvestment campaigns. "We hope that other cities and states start picking this up. This could become a good national movement," Ahmad said.

Chicago's interest in tighter gun laws is particularly acute, given that it is suffering one of the worst epidemics of gang-related gun violence in the US. Last year there were 506 homicides, a rise of 16% on the previous year.

Already this year there have been at least 16 violent deaths. The spate of murders are heavily concentrated among black teenagers living in the poor neighbourhoods of Chicago's South Side.

Harold Pollack, co-director of the University of Chicago's Crime Lab, which evaluates violence prevention efforts, said that though the city was by no means the most dangerous place in America – as suggested by some sensationalist media coverage – it did have a serious problems with guns on the streets. Chicago police capture every year six times as many illegal guns than New York City, even though it has a much smaller population.

Pollack said that since starting as mayor in 2011 Emanuel had been making sensible moves to combat the violence, though it might take some time before the results are felt. He applauded the mayor's move to disinvest from assault rifle manufacturers, saying it could change the public conversation.

"We need to ask: when did it become okay to market and encourage the proliferation of such lethal weapons that are so damaging in civil society?" Pollack said.

Emanuel has a patchy record on campaigning for gun controls. As an adviser to Bill Clinton in the White House in 1994, he was part of the team that saw the introduction of a federal ban on assault rifles that lapsed a decade later.

But when he acted as Obama's chief of staff between 2009 and 2010, Emanuel made an about-turn, keeping any talk of gun controls off the White House agenda, mindful of the damage that might cause to the president's hopes of re-election in 2012.

The mayor has indicated that he will put forward a gun ordnance that would impose stricter conditions on gun sales and ownership within Chicago's city limits. Though details of the ordinance remain sketchy, it is being billed as a unilateral act on the part of an activist mayor who has grown tired of waiting for Illinois legislature to enact a state-wide ban on assault rifles.

Last month a federal court struck down the state's longstanding ban on carrying a concealed weapon in public places on grounds that it was unconstitutional. Illinois was the only remaining of the 50 states to have such a prohibition.

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