Jordan's King Abdullah (left) arrives to have a meeting withThe Prince of Wales as part of a NATO summit at the Celtic Manor Resort in Newport, Wales.
The Prince of Wales hosted a cultural evening showcasing Welsh food, music and people for world leaders on the first day of the NATO UK summit this evening.
President Obama has become the first serving US president to visit Wales and he praised the nation and its people.
The US leader said when he arrived at the reception that "you can see natural beauty, the wonderful people, great hospitality" and he went on to urge people to visit the nation.
Peter Hemstock, 37, a secondary school teacher from Treuddyn near Wrexham, said his daughter Elin Hemstock, was one of a number of schoolchildren from across Wales who were chosen to attend the reception after their messages of hope had been chosen.
His daughter's card read: "I want to live in a world where people from different countries and cultures live in peace together."
Speaking about Mr Cameron, the teacher added: "He read my daughter's message and said that's what we're been talking about today."
Among the many leaders who attended the reception ahead of a Nato dinner in nearby Cardiff were German chancellor Angela Merkel and Canadian prime minister Stephen Harper.
On the menu at the drinks and canapes event were classic dishes such as Welsh rarebit, cured Welsh salmon and goat's cheese tartlet, and on hand to wash them down were local beers and wines from France and Chile.
The Prince greeted all his guests with a handshake and a brief word and at one point Mr Cameron joined him and when Nato secretary general Anders Fogh Rasmussen arrived, the Prime Minister said: "He's done a brilliant job, kept us to time, which is very difficult."
Before hosting the event, The Prince held separate meetings with King Abdullah II of Jordan and Turkey's newly-elected President Recep Tayyip Erdogan.
The Prince of Wales with the crew during a visit to the French warship La Motte-Picquet in Roath Basin, Cardiff Docks where the ship is docked as part of the NATO summit.
Earlier in the day, The Prince as Admiral of the Fleet, also visited the destroyer HMS Duncan, which is in Cardiff for the summit.
The Prince of Wales took part in a number of NATO exercises when he was himself a serving Royal Navy officer, including in the Atlantic, Mediterranean, North Sea, and with NATO allies in the West indies.