China sanctioned 10 US defense firms on Thursday over arms sales to Taiwan, its second round of measures against American companies over the issue in less than a week.Subsidiaries of Lockheed Martin, General Dynamics, and Raytheon that had “participated in selling arms to Taiwan” were added to China’s “Unreliable Entities List,” the country’s Ministry of Commerce announced Thursday.They will be prohibited from import and export activities or making new investments in China, while their senior managers will be banned from entering the country, the ministry said.For all the latest headlines follow our Google News channel online or via the app.Last Friday China announced sanctions on seven US military-industrial companies, including Boeing subsidiary Insitu, also over US military assistance to Taiwan.The self-ruled island is a key point of contention between Beijing and Washington.China claims Taiwan as part of its territory and has said it will not renounce the use of force to bring it