North Korea and China signed preliminary trade deals worth $1.6 billion at their annual trade fair, a roughly 10 percent gain compared to deals signed at last year's exhibition, according to a Chinese official on Thursday.

North Korea and China have jointly held the trade fair in October since 2012 in the Chinese border city of Dandong, and this year's four-day fair ended on Sunday. Last year, the two nations inked trade deals worth $1.36 billion.

Pan Shuang, deputy mayor of Dandong, told the International Business Daily newspaper that about 100 North Korean business entities attended the North Korea-China Economic, Trade, Culture and Tourism Expo.

The number of North Korean business entities attending this year was similar to last year, but Pyongyang sent trade officials and diplomats to this year's exhibition, Pan said.

At this year's fair, North Korea and China also agreed to launch new tour routes linking the North's border town of Sinuiju and Dandong, Pan said.

North Korea and China "further solidified their trade bridge through a wide range of exchange and cooperation" during the trade fair, Pan said.

China is North Korea's economic lifeline and diplomatic backer, although their political ties remain strained over the North's defiant pursuit of nuclear weapons.

Political relations between North Korea and China showed signs of a thaw after Liu Yunshan, the Chinese Communist Party's fifth-ranked official, held talks with North Korea's young leader Kim Jong-un earlier this month in Pyongyang. (Yonhap)