A US rule being used to look into Beijing's trade practices is too out of date to provide effective measures to relieve its trade deficit with China, and international trade friction can never be solved through unilateral acts, senior experts from both countries said.

The US trade representative initiated the investigation on Friday under Section 301 of Trade Act of 1974, examining China's intellectual property policies and practices. That came just four days after President Donald Trump signed a memorandum authorizing the trade representative to determine if an investigation was necessary.

The move by the United States signals that the current bilateral economic and trade relations are "at a crossroads", said Wei Jianguo, vice-president of Beijing-based China Center for International Economic Exchanges.