MEXICO CITY, Sept 26 (Reuters) - Mexican prosecutors said on Friday authorities had arrested three suspected drug hitmen who admitted to lobbing grenades into a crowded plaza during independence day celebrations, killing eight people.

The attack on revelers celebrating Mexico's national holiday on the night of Sept. 15 appeared to be the first major strike by the drug cartels on the public, raising the stakes in a drug war that has killed around 3,000 people this year.

The three men said they were members of the Zetas, the feared armed wing of the east coast Gulf Cartel formed by army deserters, the Mexican attorney general's office told a news conference.

"They gave statements to federal authorities admitting responsibility for detonating grenades during the celebrations," said Maricela Juarez, head of the organized crime investigations unit.

All three suspects appeared before the media with bruises on their faces and one was in a hospital gown. They were handcuffed and detained by guards wearing ski masks to protect their identities.

The back-to-back grenade blasts took place in the central square of President Felipe Calderon's home city of Morelia. The images of wounded women and children shocked a country used to daily murders of members of drug gangs, the police and the military.

Since Gulf Cartel leader Osiel Cardenas was captured and extradited to the United States last year, local media say the Zetas, infamous for their brutality, have taken more control of day-to-day cartel business.

Calderon has launched a frontal assault on Mexico's powerful drug gangs since taking office at the end of 2006, deploying thousands of soldiers and federal police to violent hot spots around the country.

His crackdown has led to large seizures of drugs, arms and cash and a number of arrests but drug killings have soared. (Reporting by Armando Tovar; Writing by Mica Rosenberg; Editing by Eric Walsh)

AlertNet news is provided by