A woman lights candles at the Erawan shrine, the site of Monday's deadly blast, in central Bangkok, Thailand, August 18, 2015. [Photo/Agencies]

The number of Chinese nationals killed in Monday night's explosion in Bangkok rose to seven on Wednesday, five from the mainland and two from the Hong Kong Special Administrative Region, according to the Chinese embassy in Thailand.

The bombing had left 20 dead and 125 injured as of Tuesday noon, Thai PBS reported. The dead included two Malaysians, and one from Singapore, Indonesia and the UK.

Another 26 Chinese - 19 from the Chinese mainland, five from Hong Kong and two from Taiwan - were hospitalized, the embassy said.

Among the hospitalized Chinese, 10 were in serious condition in the intensive care unit, seven from the mainland, two from Taiwan and one from Hong Kong.

Relatives of the injured Chinese started arriving in Bangkok on Tuesday. The Chinese embassy arranged for volunteers to assist at airports and hotels.

Foreign Ministry spokeswoman Hua Chunying said on Tuesday that China strongly condemns the explosion, and expresses its deepest grief for the victims and condolences to the bereaved families.

"China will remain in close contact with Thailand, make the best arrangements for the deceased and the injured, and take active measures to ensure the safety and interests of Chinese people and institutions in Thailand," she added.

Experts investigate the site of the deadly blast at Erawan Shrine in central Bangkok on Tuesday. The explosion on Monday night killed 20 people. Athit Perawongmetha / Reuters