WASHINGTON (AP) — President Barack Obama says Burundi isn't making enough progress toward establishing rule of law and will be removed from a U.S. trade preference program for African countries.

The African Growth and Opportunity Act provides duty-free treatment to U.S. imports of certain products from eligible sub-Saharan countries.

In a letter to lawmakers, Obama cites a worsening crackdown on opposition members, including assassinations, by Burundi's government as the basis for his decision to delist the country on Jan. 1. The government has also blocked opposing parties from holding organizational meetings and campaigning.

The White House released Obama's letter Friday.

President Pierre Nkurunziza's decision in April to seek a controversial third term, which he won, has sparked killings and arrests.

More than 200,000 people have fled the East African country as a result.