Trade ministers from 12 nations around the Pacific Rim are meeting on the Hawaiian island on Maui to negotiate a trade pact.

U.S. Trade Representative Michael Froman told his counterparts at the start of the talks at the Westin Resort in Kaanapali (Kah-AH-nah-pah-lee) on Tuesday that tough political issues remain to be resolved. He says as anyone who has ever been involved in trade negotiations knows, those last issues are always the most difficult.

The agreement would lower tariffs and other trade barriers while also setting labor and environmental standards for its participants.

Other nations negotiating the deal include Australia, Mexico, Japan, Singapore and Vietnam. Together, the countries account for 40 percent of the world's economic activity.

The ministers will be meeting on Maui through Friday.