Sen. Edward Markey is calling on President Donald Trump to commemorate the slaughter of more than a million Armenians by Ottoman Turks a century ago as the first genocide of the 20th century — something Turkey has refused to do, the Associated Press reports.

Massachusetts is home to a large Armenian community and includes the genocide in its public school curriculum. April 24 commemorates the day the killings began in 1915.

When he ran for president, Barack Obama promised to recognize the killings as genocide.

In office, he stopped short of doing so, instead calling the killings the first mass atrocity of the 20th century and a tragedy that must not be repeated.

Markey, a Democrat, noted Friday that past Republicans, including former President Ronald Reagan have labeled the mass killing as genocide.