"The United States made some of the worst Trade Deals in world history. Why should we continue these deals with countries that do not help us?" Trump tweeted before boarding a plane to Poland with first lady Melania Trump and embarking on his second international trip since taking office.
During his four-day trip, Trump would travel to Poland and then to Germany to attend the G-20 Summit which among others is being attended by Prime Minister Narendra Modi.
"Getting ready to leave for Poland, after which I will travel to Germany for the G-20. Will be back on Saturday," he wrote.
Shortly before his departure, Trump also lashed out at China for failing to rein in Pyongyang's nuclear ambitions.
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"Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us - but we had to give it a try!" Trump said in an early morning tweet.
On the sidelines of the G-20 Summit, Trump is scheduled to meet for the first time his Russian counterpart Vladimir Putin.
Trump who had a successful meeting with Prime Minister Modi at the White House last week, is likely to interact with the Indian leader on the sidelines of the G-20 Summit.
No bilateral meeting between the two leaders have been scheduled so far.
Modi would be arriving in Germany after his historic trip to Israel, the first by an Indian prime minister.
White House officials said the North Korean issue is expected to dominate during Trump-Xi meeting in Germany.