Venezuelan migrants flown to the upscale Massachusetts island of Martha’s Vineyard sued Florida Governor Ron DeSantis and his transportation secretary on Tuesday for engaging in a “fraudulent and discriminatory scheme” to relocate them.

The lawsuit, filed in federal court in Boston, alleges that the migrants were told they were going to Boston or Washington, “which was completely false”, and were induced with perks such as McDonald’s gift certificates.

“No human being should be used as a political pawn,” said Ivan Espinoza-Madrigal, executive director of Lawyers for Civil Rights, which is seeking class-action status in the lawsuit filed on behalf of several migrants who were aboard last week’s flights and Alianza Americas, a network of advocacy groups.

“It is opportunistic that activists would use illegal immigrants for political theatre,” said Taryn Fenske, Mr DeSantis’ communication director, in a statement late on Tuesday.

The lawsuit, which also names Florida secretary of transportation Jared W Perdue as a defendant, alleges migrants were induced to cross state lines under false pretences, a line that some Democratic officials are using to urge a federal investigation.

On Monday, Javier Salazar, the sheriff of Bexar County, which includes San Antonio, opened an investigation into the flights, but the elected Democrat did not say what laws may have been broken. California Governor Gavin Newsom and US Representative Joaquin Castro, whose district includes San Antonio, have asked the Justice Department to begin a probe.

Guesswork was rampant among government officials, advocates and journalists on Tuesday about Mr DeSantis’ next move, consistent with the element of surprise that he and another Republican governor, Greg Abbott of Texas, have sought to achieve by busing and flying migrants across the country to Democratic strongholds with little or no notice.

Asked on Tuesday about speculation that Mr DeSantis may send migrants to his home state of Delaware, President Joe Biden said: “He should come visit. We have a beautiful shoreline.”

Mr DeSantis declined to confirm speculation, based on flight-tracking software, that more migrants were on the move. He again defended his decision to fly about 50 Venezuelans to Martha’s Vineyard, saying their decisions were completely voluntary and, without evidence, that they were in awful condition when Florida got involved.