China has pledged to buy almost $80 billion of additional manufactured goods from the United States over the next two years as part of a trade war truce, according to a source, a target that could provide a much-needed boost for plane-maker Boeing but is being questioned by U.S. trade experts.

Under the trade deal to be signed on Wednesday in Washington, China would also buy over $50 billion more in energy supplies, and boost purchases of U.S. services by about $35 billion over the same two-year period, the source told Reuters late on Monday.

The “Phase 1” agreement calls for Chinese purchases of U.S. agricultural goods to increase by some $32 billion over two years, or roughly $16 billion a year, said the source, who was briefed on the deal.

When combined with the $24 billion U.S. agricultural export baseline in 2017, the total gets close to the $40 billion annual goal touted by U.S. President Donald Trump.

The numbers are expected to be announced at Wednesday’s White House signing ceremony between Trump and Chinese Vice Premier Liu He and represent a staggering increase over recent Chinese imports of U.S. manufactured goods. The size of the targets has raised questions af.reuters.com/article/commoditiesNews/idAFL4N29J26S about how realistic they are.

Two other sources familiar with the Phase 1 trade deal agreed with the rough breakdown of the purchases, without providing specific numbers.

A spokesman for U.S. Trade Representative Robert Lighthizer’s office could not immediately be reached for comment.

Lighthizer on Monday called the deal a “huge step forward” for U.S.-China trade relations and “a really, really good deal for the United States.” He told Fox Business Network that Beijing’s compliance would be monitored closely.

Lighthizer and his counterparts from Japan and the European Union on Tuesday took aim at China, proposing new global trade rules to curb subsidies that they say are distorting the worldwide economy.

Beijing’s subsidies to state-owned firms are expected to be addressed under a later “Phase 2” U.S.-China trade deal, but it remains unclear when those negotiations will begin.

Senate Democratic Leader Chuck Schumer warned Trump in a letter that a weak agreement that failed to address what he called China’s “rapacious trade behaviors” and structural inequities would harm U.S. workers and firms for years to come.

When the Phase 1 trade deal was struck on Dec. 13, U.S. officials said China had agreed to buy $200 billion in additional U.S. farm products, manufactured goods, energy and services over the next two years, compared to the baseline of 2017.

They said they would publish targets for the four broad areas, but would keep details of specific products classified to avoid market distortions.

The $32 billion agriculture increase over 2017 was confirmed by Myron Brilliant, the U.S. Chamber of Commerce’s head of international affairs, who spoke to reporters on Monday in Beijing.

Analysts and traders doubted whether China could absorb such a big increase. Relying on the United States so heavily could expose China to price and supply risks, they said.

Large Chinese purchases of Brazilian soybeans and Beijing’s suspension of a plan to implement a nationwide gasoline blend containing 10 percent ethanol this year have also raised questions about China’s ability to double its imports of U.S. farm products.

Trump had mainly touted the increased farm exports, which would benefit a major political constituency that has been battered by Chinese retaliatory tariffs during his 18-month trade war with Beijing.

Company executives have been waiting eagerly for details of what other U.S. goods China would be buying more of, aside from farm products, after 18 months of tit-for-tat tariffs that have stalled U.S. business investment.

The $80 billion increase for manufactured goods includes significant purchases of autos, auto parts, aircraft, agricultural machinery, medical devices and semiconductors, said one of the sources, without naming any specific suppliers.

The aircraft would likely be built by Boeing Co., the No. 1 U.S. exporter, whose new sales to China have ground to a halt over the past two years. That would be a welcome boost for the aerospace giant, where shares and earnings have plummeted as its best-selling 737 Max aircraft remains grounded due to two fatal crashes.

The source providing the purchase figures expressed skepticism about manufactured goods pledges by Beijing since the U.S.-China trade deal does not address any of the non-tariff barriers that have kept these U.S. goods out of the Chinese market for decades, including procurement rules, product standards and subsidies to Chinese state-owned firms.

With Chinese car sales flagging and excess domestic assembly capacity on the rise, China would seem unlikely to purchase significantly more U.S.-built cars. Among the most popular U.S.-built vehicles sold in China are BMW and Mercedes-Benz sport-utility vehicles.

China also has major industrial policy goals to dominate the very manufacturing sectors in which it has pledged to pump up purchases of U.S. goods, further fueling skepticism.

Many economists and experts are dubious the Phase 1 trade agreement will be implemented as written, despite what U.S. officials describe as an important enforcement clause.

If a U.S. claim of Chinese noncompliance cannot be resolved, Washington would have the right to reimpose tariffs on Chinese goods in proportion to the economic damage alleged. But nothing would preclude China from retaliating, people familiar with the deal said.

Oil traders and analysts were also doubtful whether China would be able to purchase an extra $50 billion of energy products, including crude oil, liquefied natural gas (LNG) and imports of petrochemical raw materials such as ethane and liquefied petroleum gas (LPG).