The contours of the alleged insurance fraud seemed unusual enough: The participants, men and women, were accused of improperly seeking Medicaid benefits for pregnancies, births and postnatal care.

That the defendants were Russian was, perhaps, not altogether unusual, given the number of recent prosecutions for similar insurance schemes perpetrated in New York by immigrants from the former Soviet Union.

But these were no ordinary Russians. They were diplomats posted to New York City, and their wives, accused of fraudulently applying for Medicaid benefits over the past nine years. Prosecutors characterized the scheme as an audacious swindle of the federal health benefits program for the needy, orchestrated by officials in the Russian Consulate in New York and its mission to the United Nations.

“Diplomacy should be about extending hands, not picking pockets in the host country,” said Preet Bharara, the United States attorney in Manhattan, whose office announced on Thursday that it had charged 49 past or present Russian diplomats and their spouses in the $1.5 million Medicaid fraud case.