China has decided to invest 600 million yuan ($88 million) in North Korean infrastructure such as roads around a border bridge, sources in both countries have said, raising concerns that Beijing may violate U.N. resolutions.

Chinese President Xi Jinping's leadership is scheduled to start the infrastructure investment by the end of this year, the sources said Friday. Beijing and Pyongyang have been strengthening their economic cooperation recently.

The effective economic aid would be regarded as a violation of U.N. resolutions aimed at preventing North Korea from producing nuclear weapons and ballistic missiles, U.N. diplomats said.