Feng, the Rio 2016 Olympic bronze medallist, led the field by one shot following yesterday's play but now leads by two on eight-under for the tournament. 

South Korean amateur Choi Hye-Jin is in a tie for second on six-under at the major, being held on the course owned by American President Donald Trump.

Choi, aged just 17, carded a second round three-under 69 which was the joint lowest round of the day.

The Korean is joined on six-under by compatriots Jeongeun6 Lee and Amy Yang.

The "6" in Lee's name is said to be used to distinguish her from five other Korean players.

Another South Korean, Seon Woo Bae, is in fifth place on five-under with Spaniard Carlota Ciganda tied in sixth place on four-under with three players.

They are South Korea's world number one Ryu So-yeon and compatriot In Gee Chun, as well as Japan's Haru Nomura.

Following poor weather yesterday, today's play began with 39 players completing their opening rounds.

Former champion Michelle Wie of the United States was forced to withdraw from the event with a neck injury, after just one hole of her second round.

Organisers ignored calls to move the event from Trump National, which was awarded the tournament in 2012, amid disrespectful comments made by President Trump towards women.

In October, the month before he was elected, a video from 2005 emerged of Trump bragging about how "you can do anything" to women "when you are a star".