Prague  - In what is to be a highlight of his five-nation European tour, US President Barack Obama is to deliver on Sunday in Prague a keynote speech on Europe and nuclear non-proliferation at an open-air meeting in the centre of the Czech capital.

The president is also to meet European Union (EU) leaders Sunday in Prague as part of an EU-US summit before flying to Turkey later in the day.

Obama and his wife Michelle arrived in Prague Saturday after attending a summit in France and Germany marking the 60th anniversary of the security organization NATO and a two-day meeting in London of the Group of 20 world's big economic powers.

To he held against the backdrop of historic Prague, Obama's speech comes as Central European nations mark the 20th anniversary of the fall of communism.

The president has said he will unveil his plan on ridding the world of nuclear arms in Prague with the city on a major security alert, which has included welding manhole covers shut.

Those wanting to attend Obama's speech are to undergo a security check similar to that at airports and are forbidden to bring items that could serve as weapons such as aerosol sprays, umbrellas and placards.

His meeting with EU leaders will be his first since taking office in January this year and the Prague US-EU summit is expected to focus on climate change and economic relations.

The Czech Republic is hosting the summit as it holds EU's sixth- month rotating presidency until June 30.

Obama, who has already met leaders of European heavyweights such as Britain, Germany and France during this trip, is to hold bilateral talks with Polish and Spanish leaders as well as European Commission President Jose Manuel Barroso.

The US leader is also expected to hold talks with Czech President Vaclav Klaus and outgoing Czech Prime Minister Mirek Topolanek.

Obama is the fourth US president to pay a visit to the Central European country of 10.3 million since popular uprising swept away communism in 1989.

Before his departure for Turkey, Obama is also to meet with the symbol of anti-Communist resistance, former Czech president Vaclav Havel. (dpa)