British Prime Minister Andy Burnham said Wednesday that the Labour party would not enter into a partnership with the left-wing Green Party while it maintains its recently adopted policy declaring Zionism a form of racism, condemning the motion as “antisemitic” while speaking in the House of Commons.

“It is wrong, it is antisemitic, and this side of the House will have nothing to do with it,” Burnham said in response to Conservative MP Dame Harriett Baldwin, who pressed him to rule out cooperation with the Greens following the adoption of the motion at the party’s annual conference earlier this month.

“We cannot support a partnership with a party that holds the position that has recently been adopted,” Burnham added. The statement marked a shift from his position last week, when he criticized the motion but declined to rule out a future coalition with the Greens.

Labour currently governs in coalition with the Greens on local councils in several cities including Sheffield, Lewes and Warwick, with the two parties also participating in broader governing coalitions in more than 10 other areas. A Downing Street spokesperson declined to clarify to the BBC whether Burnham’s position would affect those existing local partnerships or apply only at the national level.

The motion, approved by Green Party members at their conference in Brighton earlier this month, classifies Zionism as a form of racism and calls for a single democratic Palestinian state across historic Palestine. The decision drew condemnation from British Jewish organizations and criticism from within the Green Party.

Green Party leader Zack Polanski and several Green lawmakers, including former party leader Caroline Lucas, have also opposed the motion.