Philippines' Michael Christian Martinez skates during the figure skating training session at the Iceberg Skating Palace at the Sochi 2014 Winter Olympics
Philippines' Michael Christian Martinez skates during the figure skating training session at the Iceberg Skating Palace at the Sochi 2014 Winter Olympics, January 31, 2014.REUTERS/Grigory Dukor

Billions of people all over the world are excitedly waiting to witness the grand opening of the XXII Olympic Games at Sochi, Russia. But a new threat of what has been called as 'toothpaste bomb' has heightened security fears around Sochi, just hours before the games would formally begin.

The United States has warned airlines flying into Russia for the event, that explosives hidden in toothpaste could be secretly smuggled into the Olympic venues.

The latest alert has affected flights travelling into Russia as the country prepares for the grand opening show that is expected to start on Friday evening,  BBC News eported citing Department of Homeland Security.

Authorities in Russia are said to be confident about the safety of Sochi and the Olympic venues, according to  CNN.  Yet, the U.S. intelligence is intercepting increasing chatter that is worrisome for areas outside Sochi, including regional transportation links.

The concern about the toothpaste tubes is mostly on flights from Europe and Asian countries, as the United States has less intelligence sharing with those nations.

Fears were raised at the wake of two suicide bombings in Volgagrad in December, located less than 1000 km from Sochi, and numerous other threats from Islamist militants in the Caucasus region. Russia has beefed up security in and around Sochi creating what has been called a 'Ring of Steel'. Vehicles registered outside Sochi area will not be allowed, while tight security has been arranged both at the entrance of the city as well as the entrance of the Olympic venue.

Meanwhile, the much-anticipated opening ceremony of the 2014 Winter Olympics will take place at Fisht Olympic Stadium in Sochi, on February 7 at 20:14 pm (Moscow Time). Among other guests, President of the Government of Morocco, Abdelilah Benkirane; King Willem-Alexander, Queen Maxima and Prime Minister Mark Rutte of Netherlands and President Biktor Yanukovych of Ukraine are expected to be present for the function.