Luft, a citizen of the United States and Israel, is accused of recruiting and paying a former high-ranking US government official on behalf of principals based in China in 2016.
Dr. Gal Luft insists the charges made against him are entirely false and issued new allegations of corruption against US President Joe Biden.
"On behalf of the people of the United States, I extend our best wishes to the people of Israel as they celebrate 75 years of statehood," the President wrote.
Biden aides have ramped up planning for the long-expected launch of the president's bid for a second, four-year term in 2024.
Biden's expected pitch is to "finish the job" after a first term that included several legislative wins, federal funds to tackle the COVID-19 pandemic and for new infrastructure.
Russia has not made public any evidence to support the charges, under which Gershkovich faces up to 20 years in jail.