Armed robbers threatened to explode a hand grenade during a raid on an IKA social security office in northeastern Athens yesterday which netted the two thieves some 200,000 euros, police said. The men burst into the building in Aghioi Anargyroi at around 10.30 a.m. just as a security guard was about to leave a sack of cash he had unloaded from an armored truck at the cashier’s office. The suspects pulled out handguns and a hand grenade as they grabbed the money and ordered the cashier to open up the safe. They took more cash from the safe and then ran out of the building, police said. An armed security guard ran after them and fired a warning shot into the air but the two suspects escaped on foot after failing to ride off on a stolen motorcycle they had parked outside the IKA office.