A video of the incident shows Grisham inside the Freedom House in the Demilitarized Zone (DMZ), that divides the two Koreas, on Sunday pushing an aide as some North Korean security guards tried to prevent members of the American press pool from entering the room where Trump and Kim were meeting.
White House and foreign affairs correspondents tweeted about the encounter, saying Grisham got into a struggle with North Korean guards to ensure reporters had access to the meeting.
In a Twitter post, CNN's Jim Acosta said: "New WH Press Secretary Stephanie Grisham got into a scuffle with the North Koreans to move members of the WH press pool into position to cover Trump and Kim, I'm told. Grisham was a bit bruised. Source called it an all out brawl."
CNN's Allie Malloy tweeted: "Grisham was seen on camera pushing back North Koreans who were blocking US press. Shouting "Go! Go!" as she created a path for press to join the Trump-Kim meeting."
Trump on Sunday made history by becoming the first US President to set foot into North Korea. The US President and Kim two met for nearly one hour at the Freedom House on the South Korean side of the DMZ.
This was the first time for leaders of the two nations to hold a meeting at Panmunjom since the Korean War ended with the Armistice Agreement in 1953.
Kim called the meeting a "historic moment", adding that the crossing reflected his decision to open a new future in Pyongyang-Washington relations.
They were later joined by South Korean President Moon Jae-in.
( With inputs from IANS )