It's customary for new U.S. citizens to receive a letter signed by the president welcoming them as Americans, but typically that letter comes from the current U.S. president.

Not so for the husband of Aisha Sultan, a syndicated columnist at the St. Louis Post-Dispatch. Her husband, who is referred to in the letter only as "My fellow American," received a signed letter Friday not from President Trump, but from his predecessor, Barack Obama.

"My British-born husband takes his oath of citizenship today. In the packet for new Americans, the welcome letter from POTUS is from Obama," she tweeted.

The letter congratulates her husband for becoming an American and encourages him to become engaged and to uphold the principles of a democracy.

According to U.S. Citizenship and Immigration Services, roughly 200 of these letters have been sent out due to an administration error. A total of 300,000 applications for citizenship have been approved since Trump's inauguration.