The MTR says there has been a petrol bomb attack on an empty train in Sheung Shui. The railway company said objects had also placed on tracks nearby.
East Rail trains are only running between Hung Hom and Tai Wai.
At least 18 other MTR stations have closed early. Services are due to end at 11.30 pm on weekdays this week.
On the Tsuen Wan and Kwun Tong lines, Tsim Sha Tsui, Yau Ma Tei, Mong Kok, Kwai Fong, Whampoa, Wong Tai Sin and Kowloon Bay are now closed.
Tseung Kwan O and Hang Hau are closed on the Tseung Kwan O Line.
On the West Rail, Long Ping and Tuen Mun are closed.
On the Ma On Shan Line, Che Kung Temple, Sha Tin Wai, City One, Heng On and Ma On Shan are closed.
And on the Island Line, Causeway Bay and Sai Wan Ho are shut.
Almost all light rail services are suspended after the MTR said rioters blocked roads and damaged trains.