Reporters Without Borders voiced concern today about a blast that shook the headquarters of the state TV company in Tbilisi on the evening of 3 December. The explosion caused damage but no injuries and did not interrupt broadcasting. "We call on the authorities to carry out a rapid and effective investigation to avoid creating a climate of impunity that could encourage more attacks against the news media in the run-up to the presidential election of 4 January," Reporters Without Borders secretary-general Robert Ménard said. State prosecutor Nugazar Gabrichidze described the explosion as a terrorist act and said an investigation was under way. Interior ministry spokesperson Nika Laliachvili said the size of the charge was equivalent to about 300 grammes of TNT. She said an anonymous telephone call was received after the blast in which caller said: "This is just the beginning. We are going to blow up the whole building." Interior minister Giorgy Baramidze said the attack should be viewed as an attempt to increase tension before the presidential election.