Belgrade, September 11 (Beta) - Yugoslav Interior Minister Zoran Zivkovic described the terrorist attack on the US as "a black day for mankind".

"This came as a big surprise. It is obvious that terrorism has managed to reach every single corner of the world. Nothing will ever be the same", Zivkovic told Beta news agency.

Zivkovic said that security was stepped at the US embassy building and other embassy buildings around Belgrade, adding that he expected a full investigation into this violent attack.

"Experts on terrorism say this action involved a large number of people and that at issue here is a brigade of fanatics, not a small group", Zivkovic said, adding that the perpetrators had to be brought to justice so that a similar attack would never happen again.

Zivkovic called for a coordinated international response to terrorism, saying it is not enough just to find the culprits. "There are many terrorist groups throughout the world, many claim they are being backed up by different states, military or financial entities. It is clear that there has been no serious crackdown on terrorist activity so far", Zivkovic said.