China and the United States have agreed to remove additional duties on each other step by step as they make progress in reaching a comprehensive trade deal, the Ministry of Commerce said on Thursday.

Over the past two weeks, the two negotiating teams had serious and constructive discussions and agreed to remove the additional duties imposed on each other's products in different phases after they make progress in reaching a deal, ministry spokesman Gao Feng said at a weekly briefing.

If China and the US reach a phase-one deal, both sides should simultaneously undo existing additional tariffs in the same proportion, which is an important condition for signing a preliminary agreement, Gao said.

"As for how much of the tariffs should be removed, the two countries can negotiate based on the content of the phase-one deal," he said.

The trade conflict began because of additional tariffs, so a truce should be reached through tariff elimination, he added.

After the yearlong trade dispute, the world's two largest economies have essentially completed their technical consultations regarding part of the text for the phase-one deal outlined in early October.

It had been reported that the two sides might sign the deal during the now-canceled Asia-Pacific Economic Cooperation Economic Leaders' Meeting, which had originally been scheduled for later this month in Chile.

Asked about the possible location and timing for signing the deal, Gao said he had no further information.

A US anti-tariff advocacy group said on Wednesday that US consumers and businesses paid an additional $38 billion in tariffs from February 2018 to September 2019 due to the trade conflict.

In September, US consumers paid $7.1 billion in tariffs, up 59 percent year-on-year, according to Tariffs Hurt the Heartland, a group supported by more than 150 business and agricultural trade associations.

The advocacy group found that US consumers paid an additional $905 million in the first 30 days since part of additional tariffs on $300 billion worth of Chinese imports took effect on Sept 1.

"This data offers concrete proof that tariffs are taxes paid by US businesses, farmers and consumers — not by China," said Jonathan Gold, a spokesman for Americans for Free Trade — a coalition of US businesses, trade organizations and workers against tariffs. "This is why removing tariffs must be a part of the phase-one deal," Gold said.

Wei Jianguo, vice-chairman of the China Center for International Economic Exchanges, said it is urgent for China and the US to reach consensus on a mutually beneficial deal. He said he is optimistic that the two countries will solve their economic and trade issues peacefully.

In another development, the General Administration of Customs and the Ministry of Agriculture and Rural Affairs are studying lifting the restrictions on US poultry product exports to China, Xinhua News Agency reported on Thursday.

Xinhua contributed to this story.