Lobbyists representing the Saudi government reserved blocks of rooms at President Trump’s D.C. hotel within a month of Trump’s election in 2016 — paying for an estimated 500 nights at the luxury hotel in just three months, according to organizers of the trips and documents obtained by The Washington Post.

At the time, these lobbyists were reserving large numbers of D.C.-area hotel rooms as part of an unorthodox campaign that offered U.S. military veterans a free trip to Washington — then sent them to Capitol Hill to lobby against a law the Saudis opposed, according to veterans and organizers.

At first, Saudi lobbyists put the veterans up in Northern Virginia. Then, in December 2016, they switched most of their business to the Trump International Hotel in downtown Washington. In all, the lobbyists spent more $270,000 to house six groups of visiting veterans at the Trump hotel, which Trump still owns.

Those bookings have fueled a pair of federal lawsuits alleging Trump violated the Constitution by taking improper payments from foreign governments.