BEIJING (AP) -- China's trade with its close ally North Korea nearly doubled in the first seven months of the year compared with the same period in 2010, state media reported Sunday.

The 87 percent increase to $3.1 billion was announced at the start of a visit to the North by Chinese Vice Premier Li Keqiang that reaffirms strong ties between the communist neighbors.

No agenda for Li's visit has been announced, although he's likely to meet with North Korean leader Kim Jong Il and push again for Pyongyang to rejoin long-stalled six-nation nuclear disarmament talks.

“The economic and trade cooperation between the two countries has shown great potential, with bilateral trade and investment volume reaching new highs,” the official Xinhua News Agency said, citing the Chinese ambassador to Pyongyang, Liu Hongcai.

North Korea relies heavily on China for food and fuel aid, as well as many ordinary consumer products. Chinese companies are the main investors in North Korean mining operations, and the sides recently signed agreements on road building and jointly developing an industrial park on an island near the Chinese city of Dandong.

While growing, bilateral trade between China and North Korea is dwarfed by economic ties between China and the North's archrival, South Korea. China is South Korea's largest trade partner.

Trade between Beijing and Seoul rose more than 20 percent in the first eight months of the year to $159 billion and is expected to hit about $250 billion for all of 2011.