At least 245 people were killed and 48 others injured in a fire early Sunday at a nightclub in the Brazilian city of Santa Maria, officials said.

The blaze started around 2:30 a.m. at the Kiss nightclub in Santa Maria, a city of 261,000 in Rio Grande do Sul state.

The city is home to eight universities and students from one of the schools were having a party at the club when the fire started.

"It all started because they used fireworks in an enclosed space. That caused a fire and very toxic smoke that spread rapidly," Rio Grande do Sul fire chief Col. Guido de Melo said.

One of the bands performing at the club fired a flare, starting the blaze, club security guard Rodrigo Moura told the Diario de Santa Maria newspaper.

Between 1,000 and 2,000 people were packed into the establishment when the fire started, Moura said.

Patrons tried to push their way out of the nightclub amid the smoke, trampling many people, officials said.

The city will observe a 30-day mourning period, Santa Maria Mayor Cezar Schirmer said Sunday.

President Dilma Rousseff, who was attending the CELAC-EU summit in Santiago, Chile, cancelled all of her events and traveled to Santa Maria to express her support for the relatives of the victims and offer assistance. EFE