BEIJING (Reuters) - China's commerce ministry said on Wednesday that it had added four U.S. companies to its so-called "Unreliable Entity List" for their involvement in arms sales to Taiwan, which China regards as part of its territory.

The blacklisted companies, which include Pacific Rim Defense and Summit Technologies Inc., will be banned from exporting to and importing from China or making new investments in the country, according to the commerce ministry.

(Reporting by Beijing Newsroom)