(AFP) - China's Feng Shanshan shook off persistent rain and the commotion of a presidential visit on Friday (July 14) to fire a two-under 70 and stretch her US Women's Open lead to two strokes.

Feng had three birdies and a bogey for an eight-under 36-hole total of 136.

That was good enough for a two-stroke lead over South Korea's Lee Jeong Eun (69), Amy Yang (71) and Choi Hye Jin (69), who all shared second on 138.

Choi, a 17-year-old amateur, teed off on 10 and joined Feng atop the leaderboard after a burst of four straight birdies at 18, one, two and three. But she faded with bogeys at the seventh and eighth to join her compatriots on six-under.

Lee, last year's KLPGA Rookie of the Year playing her first tournament in the United States, set an early target with a second straight 69 on a rainy morning at Trump National Golf Club.

She birdied the second, took her lone bogey at the fifth but closed the front nine with a birdie and added back-to-back birdies at the 14th and 15th.

She was eventually joined by Choi and Yang, who went into the second round one stroke behind Feng and fired a second-round 71.

Feng said she was not bothered by the sometimes heavy rain that fell through much of her round, and she did not get too distracted to the arrival of US President Donald Trump, who has made his namesake club in Bedminster a frequent weekend retreat this summer.

Among Feng's closest pursuers, Yang is seeking a first Major title after 16 top-10 finishes.

World No. 1 Ryu So Yeon carded an even par 72 to join four players sharing sixth on 140 that also included South Korean Chun In Gee, Japan's Haru Nomura and Spain's Carlota Ciganda.