U.S. President Barack Obama arrived in the Czech capital Thursday morning, just hours before the signing ceremony of a new U.S.-Russia nuclear arms reduction treaty.

Graphics shows content of new U.S.-Russia pact which will be signed on April 8 in Prague. [Zhang Liyun/Xinhua]

The president's Air Force One landed at the Stara Ruzyne Airport at around 9:10 a.m. local time (0710 GMT). It is Obama's second trip to Prague since he took office. On April 5 last year, Obama delivered a speech in Prague, outlining his ambitious goal of a world without nuclear weapons.

He was heading to the Prague Castle, the seat of the Czech presidency, to sign the treaty with his Russian counterpart Dmitry Medvedev at around 11:00 a.m. local time (0900 GMT).

The two presidents will hold talks just before the signing of the new START treaty to replace the 1991 Strategic Arms Reduction Treaty (START) that expired on December 5.

Under the new pact, the two countries agree to reduce their deployed nuclear warheads to 1,550 each, or 30 percent below the current level of 2,200, and cut the launchers below 700 each.

The new treaty is widely seen as a concrete step for "resetting" U.S.-Russia ties and is expected to give new impetus to the world's nuclear non-proliferation process.

Czech authorities has beefed up security in the capital and reportedly deployed some 5,000 police. The Prague Castle has been closed to visitors since Wednesday.