Cuba and the US have formally restored diplomatic relations after an agreement struck last year putting aside decades of hostility came into force.
Just after midnight local time, the diplomatic missions of each country became full embassies.
US Secretary of State John Kerry is due to hold talks with his Cuban counterpart Bruno Rodriguez later in the day in Washington.
Despite the historic shift, both sides admit to lingering difficulties.
There were still “issues that we don’t see eye to eye on”, a US state department spokesman said.