Mexico City  - Two suspects who were in hospital recovering from a traffic accident were detained by the military Thursday in Mexico as investigators probe their connection with a grenade attack that left seven people dead in the western state of Michoacan Monday.

The two men, aged 19 and 26, are natives of Michoacan. Their van was overturned early Tuesday as they drove at a high speed through a road in the state of Zacatecas.

Mexican television showed how the two men - one of them in a stretcher - were taken out of the Zacatecas General Hospital by armed military personnel who took them to a military facility in Zacatecas.

Unconfirmed reports said that one of the suspects had wounds caused by splinters or shells, and the van apparently contained evidence tying the men to organized crime.

Two grenades were thrown into the crowd in the Michoacan capital Morelia, the hometown of Mexican President Felipe Calderon, as they commemorated the Cry of Independence - the midnight start of Tuesday's Independence Day celebrations and one of the most festive holidays in Mexico.

The office of the Attorney General was initially cautious about laying blame, but Mexican society blamed drug cartels for an attack that also left over 100 people injured. Some lost limbs in the attack, and many remained in serious condition Thursday.

Michoacan is the place where Calderon's government launched a widespread police-military operation against drug trafficking when he was inaugurated as president in December 2006.

The daily El Universal said a dispute within the Michoacan drug gang known as La Familia (the family) and another between several groups for strongholds and deals with the authorities were at the root of the attack.

However, La Familia said they were not involved and blamed rival drug gang Los Zetas, in an anonymous text that made its way to editorial offices of Michoacan dailies.

"La Familia rejects the cowardly acts that have been perpetrated across the country by a cowardly and criminal group called Los Zetas, a criminal group that is used to being hired to kill, extorting, kidnapping and stealing," the text said.

Los Zetas were until recently considered to be the armed wing of the Gulf Cartel, but they recently separated from the cartel to operate independently, according to media reports that cite official information. (dpa)