Lexi Thompson and Ai Miyazato share the lead at the halfway mark of the ANA Inspiration in California.

Thompson fired a four-under 68 at the year's first major on Friday, moving into seven under.

Miyazato put together another decent round, shooting a 70 to be alongside the American atop the leaderboard at Mission Hills Country Club.

Japan's Miyazato, eyeing her first major title, shared the overnight lead with Azahara Munoz, who struggled in the second round.

The Spaniard produced a six-over 78 that included a double bogey and four bogeys to fall to one over overall.

World number one Lydia Ko is lurking in a tie for third at six under after a 68.

Suzann Pettersen, a two-time major winner, is alongside her, as are Lizette Salas (67), Park Sung-hyun (67), Chun In-gee (69) and Lee-Anne Pace (70).