The aftermath of an arson attack in the Greek capital Athens.<br/> <br />In the early hours of Wednesday morning, several attackers drove a van loaded with gas canisters and cans of petrol into the ground floor of a Microsoft building.<br/> <br />The attack, which took place around 4 a.m. local time, caused extensive damage to the lobby and ground floor, and minor damage to the first floor - but no injuries.<br/> <br />Police said the perpetrators drove the van through the building's entrance, and then set it alight once inside.<br/> <br />Police also said at least two people wielding pistols and a machine gun kept security guards away as they carried out the attack.<br/> <br />Microsoft said it would now shut its office in the city while it assessed the damage.<br/> <br />In the past, anarchist groups have attacked large international companies with gas canisters as a symbolic gesture against capitalism, but police say it's too early to say who was behind Wednesday's attack.<br/> <br />Travis Brecher, Reuters