Residents of the District of Columbia will be able to legally possess small amounts of marijuana starting Thursday, Reuters reports. District of Columbia voters approved an initiative in November to legalize possession of marijuana. Republicans on the U.S. House of Representatives Oversight Committee say the measure is illegal.

Selling marijuana is still illegal, but transfers of up to one ounce are allowed, the article notes. The law allows adults to possess up to two ounces of marijuana and to grow six plants, including three mature plants. Marijuana paraphernalia is legal, but smoking in public is not. Marijuana is banned in the 20 percent of the District that is federal land.

Oversight Committee Chairman Jason Chaffetz of Utah and Mark Meadows of North Carolina, who heads a committee subpanel, wrote a letter to District of Columbia Mayor Muriel Bowser stating a December spending bill barred the District from spending any funds to make marijuana legal or reduce penalties. Congress has oversight authority over the District.

Mayor Bowser said legalization would go forward despite the warnings. She argued the legalization measure was officially certified before the spending ban was put in place.