By Andrew Restuccia

WASHINGTON -- The Trump administration is examining proposals to provide cash incentives to encourage unemployed Americans to return to work amid the coronavirus pandemic, according to a top economic adviser to President Trump.

"It's something we're looking at very carefully," Larry Kudlow, the director of the White House National Economic Council, said during an interview on Fox News.

Mr. Kudlow was asked about a proposal by Sen. Rob Portman (R., Ohio) to provide a temporary $450-a-week bonus for unemployed workers returning to work, on top of their wages.

Mr. Kudlow said a provision in the stimulus law that increases unemployment assistance in every state by $600 a week for up to four months creates "a major disincentive to go back to work." He predicted that provision, which Democrats want to extend beyond its current deadline of July 31, won't be included in the next coronavirus-response package.

As for the economy, Mr. Kudlow said the U.S. is approaching a "turning-zone phase" as states begin to reopen and investors react to progress in developing a coronavirus vaccine. The Dow Jones Industrial Average rose 640 points, or 2.6%, on Tuesday.

"These signs are showing a lot more glimmers of hope and growth and the signs seem to be mounting," he said.

Earlier Tuesday, the president touted the stock-market gains and called on states to reopen quickly.

"States should open up ASAP. The Transition to Greatness has started, ahead of schedule," he wrote on Twitter. "There will be ups and downs, but next year will be one of the best ever!"

The Trump administration in April released guidelines that said states should move to the first phase of reopening after exhibiting a downward trend of documented cases of Covid-19 or positive tests over a two-week period.

All 50 states have begun taking steps to reopen, even though many of them haven't yet met the administration's reopening recommendations. Asked whether the president is concerned about states not following the guidelines, a White House official said, "The guidelines are just that -- they are guidelines to maintain public health. They are not mandatory."

The president and his advisers believe a speedy reopening will boost the U.S. economy, potentially beginning to reverse the negative trends ahead of November's election. They have predicted that the U.S. will see strong growth in the third quarter of the year.

Mr. Trump on Tuesday defended his administration's response to the coronavirus as the U.S. death toll neared 100,000. He argued that the number of deaths would be much higher if he hadn't limited travel from China in January.

"One person lost to this invisible virus is too much, it should have been stopped at its source, China, but I acted very quickly, and made the right decisions," he wrote on Twitter.

The president has come under repeated criticism from public-health officials, lawmakers and others for his response to the outbreak, with experts faulting the administration for not doing more to set up a robust testing system earlier. Experts have also said many early cases in New York came from European nations, not China.

Write to Andrew Restuccia at Andrew.Restuccia@wsj.com