The leadership upheaval at BlackBerry Ltd. continues under interim chief executive John Chen, sources told the Wall Street Journal. According to the report, BlackBerry executive vice president of global sales Rick Costanzo will be leaving the company by early next year. One of the sources said Chris Wormald will also be gone by the end of this month. Wormald is in charge of BlackBerry's mergers and acquisitions strategy, the report said.

Their departures would come just weeks after BlackBerry's chief marketing officer, chief operations officer and chief financial officer left the Ontario-based smartphone manufacturer. Blackberry last month scrapped a plan to sell itself when it named Chen as interim chief executive, WSJ said.

Large-scale layoffs were already under way. Saddled with a large inventory of unsold phones and weak sales, BlackBerry in September announced that it would shed 4,500 employees of its workforce, the report said. 

Chen was tasked with picking up the pieces from the failed effort to sell Blackberry. The newly named chief executive was also mandated to figure out a way forward for a smartphone maker that no longer sells many smartphones. How Chen plans to do it remains unclear, WSJ said.