New York's mayor expressed outrage Monday after a mosque was hit by a firebomb in an arson spree that police said they were investigating as a hate crime.

The Imam Al-Khoei Foundation building in the borough of Queens suffered damage to the front door from a Molotov cocktail thrown late Sunday, police said. Two similar attacks occurred in the same neighborhood, including one in a convenience store run by Muslims.

The foundation, which describes itself as the biggest international Shia Muslim organization, said on its website that two firebombs were "hurled at the main entrance" but that thankfully "no major damage no injury was caused by the blast."

The statement said the foundation "reiterates its resolve to continue to serve the community and to strive to bring love where there is hatred, light where there is darkness and enlightenment where there is ignorance."

In a statement Monday, Mayor Michael Bloomberg said the three Molotov cocktail attacks "stand in stark contrast to the New York City of today that we've built together."

"Personnel from the NYPD's Hate Crimes Unit and the 103rd Precinct's Detective Squad are moving at full steam to investigate and also determine if there are any connections to incidents outside New York City," Bloomberg said.

Shortly before the mosque incident and in the same part of New York, a general store known here as a bodega was struck with a similar device, consisting of a still-undetermined inflammable liquid in a glass Starbucks cafe bottle, a police spokesman said.

A source close to the investigation, who asked not to be identified, said that "the employees are Muslim." The firebomb struck the counter area.

A third incident, occurring just one hour after the mosque attack, saw the same Starbucks bottle and accelerant weapon thrown at a private home used by a Hindu priest for ceremonies, police said. Nothing outside the house indicates its dual use as a temple, police said.

A fourth, more destructive attack on the same evening caused a major fire at a nearby private home, although there was no proof of links between this and the other incidents.

"There were no injuries, but there was extensive damage," a police spokesman said.

The source with the investigation said that in this case arson was suspected, but there was no indication of the same firebombs being used. The inhabitants, who were lucky to escape unharmed, were Christian and had no connection to the mosque or to the bodega, the source said.

Bloomberg has been a staunch defender of the city's Muslim immigrant population, notably in the furor over plans to build an Islamic center and mosque two blocks from the former location of the Twin Towers, which were destroyed in the September 11, 2001 Al-Qaeda attacks.

However, Muslim community leaders say their civil rights have been marginalized since 9/11, especially as a result of intrusive police surveillance.