Beijing, China — China said Monday it had lodged a complaint against the United States with the World Trade Organization (WTO), one day after new tariffs imposed by Washington on billions of dollars of Chinese goods came into force.

The world’s two biggest economies have been embroiled in a bruising year-long trade war which escalated further on Sunday when both sides moved ahead with fresh tit-for-tat levy hikes.

“These American tariffs seriously violate the consensus reached by the leaders of our two countries in Osaka,” Beijing’s commerce ministry said, referring to trade discussions in the Japanese city in June.

“The Chinese side is strongly dissatisfied and resolutely opposed to that. In accordance with relevant WTO rules, China will firmly safeguard its legitimate rights and interests,” the ministry added in a statement published on its website.

The complaint has been lodged with the WTO body for dispute settlement, the ministry said.

Washington’s latest levies on imports from China took effect on Sunday as it stepped up a high-pressure campaign aimed at compelling Beijing to sign a new trade deal.

The additional tariffs affected a portion of the $300 billion in goods from the Asian giant that so far had been spared.

Beijing has said it will retaliate by targeting $75 billion in US goods, beginning in part on September 1.

The trade dispute has rattled markets and hit growth across the globe, and trade negotiations between the two countries have been at an impasse for months.

US President Donald Trump and China’s leader Xi Jinping had agreed to “fully engage” on trade when they met in Osaka during the G20 summit in Japan.

But at the recent G7 meeting in France, Trump spoke of new communications between US and Chinese negotiators — giving financial markets a brief boost — while China’s foreign ministry said it was unaware of such contacts.