Maryland Governor Larry Hogan thinks President Donald Trump and his administration need to use caution when communicating about the trade war with China, and said that the administration's trade policies are worrying foreign countries.

Hogan's comments on trade policy to CNBC's "The Exchange" followed a tweet by Trump that the US will implement a 10% tariff on an additional $300 billion of Chinese imports beginning Sept. 1.

@realDonaldTrump: ...during the talks the U.S. will start, on September 1st, putting a small additional Tariff of 10% on the remaining 300 Billion Dollars of goods and products coming from China into our Country. This does not include the 250 Billion Dollars already Tariffed at 25%...

The Dow plunged more than 200 points following the news, erasing the 300-point gains earlier in the day.

Hogan said that he supports a "tough but fair" trade deal with China, but also urged caution.

"I understand the logic of setting the expectations before the negotiations take place, but look at the market reaction because of a tweet," he said. "I think we've got to be careful about how we message things."

Hogan, who recently became chairman of the National Association of Governors, said that the Association has met with foreign delegations about trade.

"We had five or six different countries' delegations that came and met with us to express concern about trade and tariffs," he said.

Hogan said these foreign delegations emphasized the detrimental impacts that Trump's trade policies could have on US states.

He said these delegations told him "'we're concerned about Washington and we want to start developing those relationships with the governors of the individual states.'"

The White House did not immediately respond to a request for comment on Hogan's remarks.

Hogan has criticized Trump and others in the Republican party, leading some to eye him as a possible Republican challenger to Trump in the 2020 Republican primary. He said in June he would not run, but has continued to voice his disagreements with Trump.

He slammed Trump on Monday for his tweets calling Baltimore a "disgusting, rat and rodent infested mess" and has questioned his party's direction under Trump.