US President Barack Obama and other world leaders sought to sharpen their skills in dealing with a potential terrorist nuclear event by taking part in an interactive nuclear war game during a security summit at the Hague Tuesday, the Telegraph reported.According to the report, German Chancellor Angela Merkel "grumbled" at the request to play games and be tested on her reactions along with Obama, British Prime Minister David Cameron, Chinese Prime Minister Xi Jingping and other world leaders.The Telgraph reported that Obama was excited about the exercise and Merkel's complaints fell on deaf ears.In the nuclear war game, demonstrated by actors in a series of videos, a "dirty bomb" attack is set to take place in a major western city, perpetrated by terrorists from an unidentified international terror organization, who stole nuclear material from a country with poor security on its nuclear stockpile.The game challenged the world leaders to take action in the face of the attack and prevent the deaths of hundreds of thousands of people."They had to give an answer on their own, in real time. It was like a test. It put them on the spot. Should they inform the public or keep them in the dark," the Telegraph quoted a diplomatic source as saying."Should they work with other countries or stand alone to try to thwart or minimize the attack? How should they make the cold calculation of how to get a more sustainable human cost in terms of deaths?" the source added.The leaders entered their answers on a touch-screen tablet against a ticking clock. They later discussed their responses.US officials stated that they intended to give the leaders a "scare you to death" shock in order drive home the importance of nuclear security."Leaders had their doubts about participation on their own without their expert civil servants. It was about discussion and problem solving without leaders relying on written statements to read out. At the end the leaders were more enthusiastic," the Telegraph quoted a spokesman for the summit as saying.