(CNN) President Donald Trump on Monday hailed an agreement between the US and Mexico to change parts of NAFTA, but a new poll has found most Americans disapprove of how he has handled trade negotiations with other countries.

Just 39% of American adults approve and 61% disapprove of how Trump has handled negotiations, according to an AP-NORC poll conducted last week and released on Monday.

The percentage of those who disapprove has increased six points since the poll was last conducted in June.

Americans are also worried about the impact of Trump's imposed tariffs on the economy and the increase in price on American goods, the new poll finds.

The effect on US jobs is the most important issue for Americans when negotiating trade agreements with other countries, with 81% saying it's extremely or very important. Another three-quarters said that the effect on US industries is extremely or very important to trade negotiations and 68% thought the environmental impact was an issue of high consideration.

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