US President Barack Obama has met Pope Francis for the first time to discuss how to fight global inequality and poverty, calling himself a "great admirer" of the pontiff.

Obama arrived at the Vatican on Thursday amid the pomp and tradition of the Catholic Church, making his way to greet the pope after a long, slow procession through the hallways of the Apostolic Palace led by colourful Swiss Guards and accompanied by ceremonial attendants.

The president bowed as he shook hands with Francis in the Small Throne Room, before the two sat down at a wooden table in the Papal Library.

"It is a great honour. I'm a great admirer," Obama said. "Thank you so much for receiving me."

Political observers said the meeting could be a bid to boost the US president's support at home among Catholic voters. It comes as Obama's administration and the Church remain deeply split on issues of abortion and contraception.

The first African-American US president spoke of the first pope from Latin America as an "inspiration" in an interview with the Corriere della Sera daily.

"The Holy Father has been an inspiration to people around the world, including me," Obama said, adding however: "It doesn't mean we agree on every issue."

Obama is wrapping up a six-day European tour that has so far been dominated by the crisis over Crimea.

Obama also met new Italian Prime Minister Matteo Renzi - the European Union's youngest government leader - who recently launched an ambitious reform agenda .

Diplomatic relations between Italy and the US are close, though Rome has been cautious about imposing sanctions on Russia over the Ukraine crisis, amid fears it would take a toll on a key market.

Source: AFP