Shortly after President Trump fired off a tweet Tuesday urging the Federal Reserve to boost the economy by slashing interest rates, Boston Fed President Eric Rosengren said cutting rates now would be a mistake.

Top Fed officials, including Rosengren, will meet Sept. 18 to determine if interest rates should decline or stay the same. Trump has tweeted 34 times in the past month demanding that the Fed lower the funds rate by a significant amount as recession fears have risen, but Fed officials remain divided on whether even a modest cut is warranted.

“This isn’t a free lunch. There are costs to accommodating at a time when the economy is doing reasonably well,” Rosengren told The Washington Post in an interview before his speech Tuesday at Stonehill College in Easton, Mass.

Rosengren said the U.S. economy is in a “relatively strong” place with low unemployment, rising wages and solid growth driven by consumer spending. He does not see a need for lower interest rates until there are clearer signs of distress from the trade war on consumers. If the Fed lowers rates too soon, he is worried it would leave little firepower left to fight bigger problems later on.

“You don’t want to apply accommodation at a time when you don’t need it, in part because you won’t have it when you do need it and in part because there are side effects from pushing interest rates very low. It encourages people to take more risk,” Rosengren said.

The benchmark U.S. interest rate is just shy of 2.25 percent, a low level by historical standards, but Trump has argued it should be 1.25 percent — if not lower.

“Germany, and so many other countries, have negative interest rates, ‘they get paid for loaning money,’ and our Federal Reserve fails to act! Remember, these are also our weak currency competitors!” Trump tweeted Tuesday, suggesting he would even favor negative rates in the United States, an extremely unusual situation where the bank pays people who take on a mortgage or borrow money to start a business.

Trump has in the past said that a swift interest rate cut by the Fed would lead the Dow Jones industrial average to climb by thousands of points. In August, the president tweeted repeated insults at Fed Chair Jerome H. Powell, calling Powell an “enemy,” “a golfer who can’t putt” and someone with “horrendous lack of vision.”

There’s widespread agreement among economists that the U.S. economy is slowing, but experts are divided on whether the nation is likely slip into a downturn by 2021. The manufacturing sector is already in a recession, business spending has dried up amid the trade war and the bond market is signaling trouble ahead, but stocks remain near record highs, companies continue to hire, and consumers keep spending.

The Fed lowered interest rates in July for the first time in over a decade, but Rosengren and Kansas City Fed President Esther George voted against the cut. Rosengren and George are two of the 10 Fed officials who will vote on the next interest rate decision in two weeks.

Wall Street investors and White House officials are watching their views closely as it is unlikely the Fed would lower rates substantially with such vocal dissents. Investors are currently betting the Fed will do a modest reduction in September and another one by the end of the year, a much more gradual downshift than what Trump wants.

Powell hinted in a recent speech that the Fed is likely to cut rates a quarter point in September to just below 2 percent, but he said there are “significant risks” from the trade war and the central bank can only do so much to minimize the negative impact.

Narayana Kocherlakota, the former head of the Minneapolis Fed from 2009 to 2015, has been one of the most outspoken voices calling for interest rate cuts, but even he said he probably would not endorse more than a small cut in September. Going lower could spook business leaders and investors, he said.

“If I were sitting in that room, I’d be pretty loathe to cut 50 basis points,” said Kocherlakota, who is now an economics professor at the University of Rochester. “There is a risk if you do cut by 50 basis points, you’re sending a message that we see something really bad on the horizon.”

Trump wants a strong economy as he campaigns for reelection in 2020, but his trade war has caused business investment to dry up and there is growing concern consumers could close their wallets as well, especially if Trump’s tariffs cause prices of shoes, clothing, phones and other popular products to jump.

“Clearly there is a downside risk that trade or geopolitical problems could escalate, resulting in a much weaker situation than is currently anticipated,” Rosengren said. “What has prevented the economy from being stronger is the slowdown occurring globally and the tariffs."

Trump’s latest tariffs on China took effect on Sept. 1, causing the prices of clothing and shoes made in China and shipped to the United States to rise.

While Rosengren said these tariffs are “likely to be more noticeable” to consumers, he still thinks consumption will remain strong since so many people have jobs and are enjoying higher pay and lower gas prices.

For the economy to grow about 2 percent, consumption only needs to expand at about a 3 percent annual pace. This spring, it grew at over 4.5 percent, according to the latest government data.

“When you have really strong consumption, it makes up for a lot of weakness elsewhere,” he said.