WASHINGTON, United States - Trade tensions between the United States and China have been escalating over the past month, following President Donald Trump's decision to impose steep tariffs on steel and aluminum imports.

Here are the main dates in the conflict between the world's two largest economic powers:

March 8
US President Donald Trump signs the order to impose tariffs of 25 percent on steel imports and 10 percent on aluminum citing national security concerns.

The goal was to address China's overproduction, but the measures also would hit allies, prompting the European Union to threaten retaliation. The administration later exempted the EU, Canada, Mexico, and 4 other economies from the duties.

March 22
The Trump administration announces punitive tariffs on about $50 billion in Chinese goods in retaliation for what it says has been the massive theft of intellectual property from American companies.

Trump gives US Trade Representative Robert Lighthizer 15 days to draw up a list of products to target, which Lighthizer said would be drawn from the goods Beijing has said it wants to dominate.

March 23
In retaliation for the US tariffs on steel and aluminum, Beijing hits back with a list of 128 products which will face duties of 15-25 percent in the event negotiations with Washington fail to resolve the dispute.

Among them are fresh fruit, pork and recycled aluminum, which accounted for $3 billion of US exports last year. Economists say this response was measured, since it does not affect the main Chinese imports from the US.

March 26
Chinese authorities urge the United States to stop its "economic intimidation" and threatens further retaliation.

April 2
China rolls out punitive measures against the 128 US products in response to steel and aluminum duties. Fruit, pork and California wine are on the hit list.

April 3
In response to the March 22 presidential order, USTR publishes the provisional list of imports that would be subject to new duties in retaliation for "the forced transfer of American technology and intellectual property."

This list, which targets imports representing approximately $50 billion, targets products from various sectors including aeronautics, information and communication technologies, and robotics and machinery.

April 4
A few hours after the publication of the US target list, Beijing responds with a list of $50 billion of US goods that will be hit with retaliation, this time including key exports: aircraft, auto and soybeans.

Trump responded in a tweet, saying, "We are not in a trade war with China, that war was lost many years ago by the foolish, or incompetent, people who represented the US."

The trade deficit with China rose to $337 billion in 2017, but Trump likes to ignore the dominant US services sector and focus only on the deficit in goods alone, which was $375 billion last year although he uses a higher figure.

"Trade Deficit of $500 Billion a year, with Intellectual Property Theft of another $300 Billion. We cannot let this continue!"

He concluded the tweet storm saying, "When you’re already $500 Billion DOWN, you can't lose!"