Closed-circuit TVs are being installed around the state guesthouse in Hanoi as Vietnam gears up to host a second summit between North Korea and the United States. 

Measures that were visibly being implemented on Tuesday were said to be aimed at boosting security for North Korean delegates who have been staying at the state guesthouse since the weekend, including North Korean leader Kim Jong-un's de facto chief of staff Kim Chang-son. 

The venue could also be used by another Pyongyang delegation spearheaded by North Korea's special representative for U.S. affairs Kim Hyok-chol, who arrived in Beijing on Tuesday en route to Hanoi. 

Four vehicles loaded with around 20 large-sized paintings were also observed entering the grounds of the state guesthouse.