China warned its companies operating in the United States on Tuesday that they could face harassment from U.S. law enforcement agencies, as it also rebuffed U.S. criticism of a trade white paper as “singing the same old tuneâ€. Relations between the world’s two largest economies have nosedived in recent months due to a bitter trade war, U.S. sanctions against Chinese telecoms giant Huawei Technologies and U.S. support for Chinese-claimed Taiwan. Tensions rose sharply after Washington slapped additional tariffs of up to 25% on $200 billion of Chinese goods, prompting Beijing to retaliate. Aft...