Toyota Motor Corp will start talks to pull out of a California-based joint venture with General Motors , a Toyota executive said on Thursday.

Toyota said earlier this month it may liquidate its stake in the Fremont, California auto assembly plant -- commonly known by its acronym NUMMI for the New United Motor Manufacturing Inc -- after GM cut operating ties to the plant in late June.

The world's two biggest carmakers aim to reach agreement on the plant's future by the end of next month, the executive said.

A Toyota official relayed to Reuters the remarks by the executive, who requested anonymity.

Options for the joint venture now include liquidation, with Toyota and GM each writing off their stakes, and a sale to another company.

Shares of Toyota closed up 1.7 percent at 3,660 yen ahead of the executive's comments.

(Reporting by Nobuhiro Kubo; writing by Yumiko Nishitani)