The Bolivian Defense Ministry was damaged today by small explosives thrown at the building in what officials said was a terrorist attack by people seeking to destabilize the government.
No one claimed responsibility for the blast, the third in a week, that caused damage to the building but no injuries.
President Carlos Mesa, a political independent who assumed power after a bloody indigenous revolt last year, is under pressure from both leftist Indian groups and right-wing politicians to resolve how Bolivia develops its vast natural gas reserves.
"This is a terrorist act with political undertones that is aimed at provoking reaction from the Armed Forces and police to destabilize the government," Interior Minister Mr Saul Lara told reporters, without naming who could be responsible.
Police said today's explosion may have been caused by someone tossing dynamite from a moving vehicle. Car windshields near the ministry building shattered from the impact.