Prosecutors in Los Angeles have filed a lawsuit that aims to close a smartphone app that is able to deliver medical marijuana to the app's users, which violates the ban on similar business operations in the city.

The filed lawsuit by the prosecutors is the latest chapter in the current struggle to keep medical marijuana in check in Los Angeles, as authorities have been unable to prevent the increasing number of shops that sell the banned substance in the city for more than a decade.

A 2013 ballot measure approved by voters, named Proposition D, banned medical marijuana business operations in Los Angeles, including the delivery of the substance. However, the same ballot measure also granted immunity with certain provisions for about 130 stores to legally continue their operations.

The lawsuit, which was filed in the Los Angeles Superior Court, is also the first instance that authorities have attempted to crack down on apps for medical marijuana, which are said to be also covered by the ban set forth by the initiative.

A Los Angeles City Attorney's Office spokesman said that the proliferation of such apps, and illegal business in general that operate for medical marijuana, would soon come to an end.

"They should continue operating at their own peril. This lawsuit sends the message that we will continue to enforce the will of the voters when they passed Proposition D," said spokesman Frank Mateljan.

The app being targeted by the lawsuit is named Nestdrop, which allows its users to order their supply of medical marijuana and have the shipment delivered to any location within Los Angeles.

Mateljan added that the operators of such delivery services and apps could possibly face criminal charges. However, for Nestdrop's case, the authorities thought that filing a lawsuit was the fastest way to be able to close down its operations.

The lawsuit is looking for a permanent injunction against Nestdrop's owners from the operations of the app, and for any future developments of similar businesses.

California was the first state that allowed medical marijuana after a state-wide vote in 1996. However, counties and cities within California have been finding it difficult to prevent the increase in number of businesses selling the substance.

An advocacy group for medical marijuana has started a signature campaign that intends to have recreational marijuana legalized in a 2016 ballot, similar to a ruling passed in Colorado in 2012.

The previous attempt to legalize marijuana in California, back in 2010 as a ballot initiative, failed.