Two days of intensive negotiations between U.S. and Japanese trade representatives ended Thursday in failure as the two sides failed to break the deadlock over the Trans-Pacific Partnership talks, clouding the prospects for a summit between U.S. President Barack Obama and Prime Minister Shinzo Abe later this month.

Visiting U.S. Trade Representative Michael Froman and his Japanese counterpart, fiscal and economic policy minister Akira Amari, held almost 18 hours of talks on Wednesday and Thursday in Tokyo.

But the two apparently failed to solve key sticking points, including those related to tariffs on Japanese automobiles and U.S. beef, pork and rice.