Bomb doesn't scare us, says Mexico City mayor

MEXICO CITY (Reuters) - Mexico City will not be intimidated by a bomb attack aimed at a police chief in the capital, Mayor Marcelo Ebrard said Tuesday.

The small homemade bomb exploded Friday and killed the man carrying it, who police say was waiting to attack a senior security ministry official. The blast badly burned a woman walking with the man and hurt a bystander.

"If the aim was to intimidate, they are not going to succeed," Ebrard said. He said the capital's police had his unlimited backing to tighten security in the sprawling capital city of 18 million.

Mexico City's top prosecutor, Rodolfo Felix, says the bomb was aimed at a senior city police official, but has not named him. He has not said whether the bomber, Juan Manuel Meza, and his companion, Tania Munoz, were working alone or for a criminal gang.

However, his reaction to the blast on Friday was that it may have been a botched attack by one of Mexico's powerful drug cartels, hit recently by a rash of arrests. He appeared to rule out Marxist rebels who bombed fuel pipelines last year.

Mexico has no known major terrorist groups, but feuding drug gangs killed more than 2,500 people last year and President Felipe Calderon deployed the army to crush them.

Drug hitmen regularly murder police chiefs and judges, and three heavily armed men arrested in January were planning to kill the country's deputy attorney general. However, gangs have not yet been known to use bombs.

The city has stepped up security since the bomb went off on Friday in a central street near the security ministry, laying on extra helicopter surveillance and adding police at the airport, underground metro stations and shopping malls. (Reporting by Miguel Angel Gutierrez; Writing by Catherine Bremer, editing by Patricia Zengerle)