By Grace Sparks, CNN

(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.

The least-concerning aspects of trade negotiation for the US were wages and working conditions in other countries (22% slightly/not at all important) and profits for American corporations (20% slightly/not at all important).

The possibility of tariffs isn't necessarily pleasing to all of the American public, with 40% opposed to the possible decision to place an import tax on certain goods brought in from other countries. That's split with the 38% who said they favored the taxes.

While 39% said they thought Trump's tariffs will increase jobs in the US (compared to 34% who said they'll decrease jobs), that comes in stark comparison to the 72% who said the tariffs put in place will increase the price of consumer goods in the US.

The other split takes place on what the tariffs will do to the economy, with similar numbers to favor/opposition. Four-in-10 said that the tariffs will help the national economy with slightly more -- 44% -- who said they will hurt.