BBC:-US President Donald Trump says he is rolling back the Obama administration’s “completely one-sided deal with Cuba”.
Speaking in Miami, Florida, he said his new policy would tighten rules affecting travel and on sending funds to the Caribbean island nation.
But he is not reversing key diplomatic and commercial ties, and will not close the US embassy in Havana.
Commercial flights from the US will continue, as will allowing Americans to return home with Cuban goods.
Mr Trump said the Obama administration’s March 2016 deal with the “brutal” Castro government was “terrible” and “misguided”.
On Friday, Mr Trump signed a presidential directive calling for tighter enforcement of a longstanding ban on American tourists going to Cuba.
The new policy bans most US business transactions with the Armed Forces Business Enterprises Group, a Cuban entity involved in all sectors of the economy.
However, it exempts air and sea travel, allowing US airlines and cruise lines to continue serving the island.