US singer Ciara has become one of the first public figures to be granted citizenship of Benin, under a new law offering nationality to the descendants of slaves.

In an Instagram post the Grammy award-winner said she was "honoured", adding "thank you Benin for opening your arms and your heart to me".

The citizenship scheme is part of an initiative by the small West African country to build ties with the African diaspora and boost cultural tourism.

Ciara, known for R&B and pop hits such as Goodies and 1,2 Step, officially became a citizen at a ceremony in the city of Cotonou.

"This act, which is symbolic, humane and historic, is not merely an administrative gesture. It is a gesture of the soul, a return to one's roots, a hand extended to those whom history, in its brutality, had torn from this land," the government said in a statement on Monday, following the ceremony.

By enacting the My Afro Origins Law last year, Benin joined countries like Ghana and Guinea-Bissau in offering citizenship to people with an African ancestor who was taken from their homeland as part of the transatlantic slave trade.

Descendants can apply to become a citizen via a recently launched website.

Just last week, Benin appointed renowned American filmmaker Spike Lee and his wife, Tonya Lewis Lee, a seasoned producer and author, as its ambassadors for African-Americans in the US.

Benin's coastline is part of what was once known as the Slave Coast - a major departure point for enslaved Africans shipped across the Atlantic Ocean to the Americas.

Between 1580 and 1727, the Kingdom of Whydah, a major slave-trading centre located on what is now Benin's coast, is estimated to have exported more than a million Africans to the US, the Caribbean and Brazil.