Authorities are investigating bias crime attacks at four locations in New York, including an Islamic centre and a Hindu place of worship, in which Molotov cocktails were hurled at the sites damaging property.
The attacks took place in Queens near New York on Sunday night in which unidentified assailants threw homemade firebombs at a house used for Hindu worship services, an Islamic centre Imam Al-Khoei Foundation, a home and a convenience store.
No injuries have been reported so far, police said.
New York Mayor Michael Bloomberg called such attacks unacceptable and said authorities are investigating the incidents.
"No matter what the motivation was of the individual who threw Molotov cocktails in Queens last night, his actions stand in stark contrast to the New York City of today that we've built together," he said in a statement.
Governor Andrew Cuomo said such attacks have no place in "our open and inclusive society and we must do all we can to ensure New York remains a safe and tolerant place for all."
Bloomberg said personnel from the New York Police Department's Hate Crimes Unit and detective squad are "moving at full steam" to investigate and also determine if there are any connections to incidents outside New York City.
A fire department official said the attacks damaged property but no one was injured.
Police said in three of the four attacks, Molotov cocktails were made using Starbucks bottles.
The first attack took place on Sunday night in a convenience store, also known as a Bodega. Then 10 minutes later, a crude firebomb was thrown at a home, which caught fire, the Islamic centre and the Hindu place of worship.
The Imam Al-Khoei Foundation has one of the most prominent Shia mosques in New York.
According to information on its website, the centre provides education, funeral services, counseling and helps organise Haj pilgrimages. It has branches in several cities, including in Montreal and Islamabad.
Police said the Hindu place of worship was a private home that was used by a Hindu priest for ceremonies, adding that from the outside the house did not look like a temple.
An Imam at the Islamic centre said about 80 people were gathered there when the firebomb was thrown inside, shattering the glass.
He said the foundation promotes work in development, human rights and minority rights as a general consultant to the Economic and Social Council of the United Nations.
The center also has a school that will resume Tuesday after holiday break.
Police, who are investigating the attacks as hate crime, said callers informed them that they saw the assailants fleeing the scenes after hurling the firebombs.
They were looking at surveillance video obtained from the Bodega and the attack on one of the houses.
The Islamic centre said on its website that two firebombs were "hurled at the main entrance" but "no major damage no injury was caused by the blast."
It 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."
Image: The Imam Al-Khoei Foundation that was hit with a firebomb on Sunday night is seen in the Queens borough of New York
Photograph: Shannon Stapleton/Reuters