Washington: The U.S. government has imposed a ban prohibiting its officials and staff from engaging in romantic or sexual relationships with Chinese nationals while stationed in China.The ban applies to all personnel working for the U.S. mission in China, including officials, staff, family members with security clearance, and contractors, according to international media reports.The directive came into effect immediately after U.S. Ambassador to China Nicholas Burns stepped down from his position in January this year. The U.S. warned that any violation of this order would lead to dismissal from duty.