(Reuters) - The U.S.-China trade deal announced here on Friday will be signed in early January, U.S. trade negotiators say.

FILE PHOTO: Containers are seen at the Yangshan Deep Water Port, part of the Shanghai Free Trade Zone, in Shanghai, China, February 13, 2017. REUTERS/Aly Song/File Photo

However, subtle but important differences between what U.S. and Chinese officials say has been agreed upon have arisen in recent days, including about timing.

The White House and Beijing have been locked in a 17-month trade war punctuated by an agreements-in-principal that fell over specific details in May.

Here are the official statements from Beijing so far:

CHINA’S PURCHASE OF U.S. GOODS

U.S. Trade Representative Robert Lighthizer told here reporters on Friday that the deal includes promises by Beijing to buy $200 billion more in U.S. goods and services over the next two years, a huge jump in China's imports of $186 billion in 2017.

Officials in China have not confirmed any dollar figure.

"Chinese enterprises will import more high-quality and competitive goods and services from countries including the United States under the WTO rules as well as market rules and business principles," Chinese officials told reporters during a press conference on Friday in Beijing, reading from a prepared statement later published here by Xinhua.

In response to reporters' questions here, Chinese officials emphasized market conditions, not specifics.

“As long as the U.S. products and services are marketable and can meet the needs of Chinese people, expanding imports from the United States is something we would like to see,” said Ning Jizhe, vice chairman of the National Development and Reform Commission.

China could “expand the scale of imports” from the United States in “energy, manufactured products, and services as needed,” he said.

A $50 BILLION FARM PRODUCTS BUY

Asked specifically about U.S. President Donald Trump's Dec. 13 claim here that China would buy $50 billion in farm products, Ning said there is "no doubt that China will increase the procurement of high-quality and market-competitive U.S. agricultural products," but said specifics were still being determined.

The implementation of the agreement will “greatly increase the agricultural products we import from the United States,” vice minister of agriculture and rural affairs Han Jun said, adding that imports of pork and poultry were “urgently needed” to stabilize the domestic market.

China “will import some wheat, corn, and rice from the United States,” Han said. But he added that China will continue to emphasize self-sufficiency in grains, rather than relying on imports. “We will firmly hold the rice bowl in our own hands,” he said, and will keep national food security the bottom line.

TARIFF ROLLBACKS

Both sides suspended tariffs due to go into effect Dec. 15. The United States cut tariffs on some $120 billion in Chinese goods by 50%, to 7.5%, while leaving in place 25% tariffs on $250 billion in goods, USTR said.

Beijing statements suggest more tariff rollbacks to come.

“Both sides have reached consensus that the U.S. side will fulfill its commitments to phase out its additional tariffs on Chinese products, so as to achieve a switch from hiking to cutting additional tariffs,” Chinese officials said on Friday.

“The United States has promised to cancel part of the tariffs that it intends to impose on China and the tariffs that have already been levied,” Liao Min, the vice director of the office of financial and economic affairs, said in response to a question on tariffs.

“The second is to increase the tariff exemption for Chinese exports to the United States,” he said, but did not elaborate.

TIMING

The United States and China will sign a deal the first week in January, Lighthizer said here on Friday.

Beijing would not confirm that timing on Monday.

"Our two sides still need to go through necessary procedures including legal reviewing and translation proofreading," Geng Shuang, the foreign ministry spokesman, said during a Monday press briefing here when asked.

“After that, we will decide when, where and how we will sign it. Working-level discussions are still going on between China and the U.S.,” he said.