Senior White House advisor Ivanka Trump and Commerce Secretary Wilbur Ross (R) arrive for the first meeting of the American Workforce Policy Advisory Board with US President Donald Trump in the State Dining Room of the White House in Washington, DC, March 6, 2019.

"This quarter's survey shows American businesses now have their foot poised above the brake, and they're tapping the brake periodically," Business Roundtable President Joshua Bolten said in a statement. "Uncertainty is preventing the full potential of the economy from being unleashed, limiting growth and investment here in the U.S."

The Business Roundtable said its members now forecast growth this year will clock in at 2.3%, down from last quarter's estimate of 2.6%. In addition, its indexes of hiring, capital investment and sales all declined.

The chief executives of the nation's biggest companies downgraded their outlook for the U.S. economy amid uncertainty over the trade war and slowing global growth, according to a new survey released Wednesday.

The Roundtable, whose chairman is J.P. Morgan CEO Jamie Dimon, blamed tension with China and the stalled free-trade agreement with Mexico and Canada for its members' downbeat assessment.

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This quarter's survey asked members to rate the impact of the trade war on their businesses over the past year. More than half of executives reported a somewhat or very negative impact on sales, while 40% of manufacturing CEOs said capital investment took a hit. The group found almost no company reported a positive impact.

Corporate executives have been among the most vocal advocates for a new North American trade agreement, while also urging the Trump administration to tamp down its rhetoric against China and hold off on tariffs. The Roundtable has also taken on controversial issues in recent months, ranging from the need for comprehensive privacy legislation to gun violence legislation to immigration. Last month, the group's members issued a statement that said shareholder value is no longer their main objective.

On Tuesday evening, a group of executives visited Camp David with President Donald Trump's daughter and advisor Ivanka Trump, Commerce Secretary Wilbur Ross and Vice President Mike Pence. The guest list included Lockheed Martin CEO Marillyn Hewson, IBM CEO Ginni Rometty and Visa CEO Al Kelly, all members of the administration's workforce policy advisory board.

On Wednesday, the executives are scheduled to visit the Boys & Girls Club of Greater Washington with the administration.

"The U.S. needs strong, sustained, long-term economic growth in order to remain globally competitive and expand opportunity for more Americans," Dimon said. "Business Roundtable CEOs stand ready to work with policymakers to address our nation's biggest challenges to create conditions for inclusive growth, investment and job creation here in America."

According to the Roundtable, the broad index of the CEOs' outlook fell 10.3 points from the previous quarter to 79.2, below the historical average but still signaling economic growth. The indexes for sales and capital investment over the next six months also dropped below their long-term averages: Sales declined 13.5 points to 91.6, while investment plunged 14.7 points to 73.4.

The index for hiring saw the smallest drop, falling 2.6 points to 72.6. That reading remains well above the index's historical average.