Another attack against reporters has taken place in the Mexican state of Veracruz, alarming human-rights authorities amid an escalation of violence against the press in Mexico.

Unknown assailants early on Sunday opened fire upon the offices of Presente, a small newspaper in the city of Poza Rica, in northern Veracruz. The attackers broke windows and set three of the newspaper's transport vehicles on fire.

The events happened just two days after the Mexico City apartment massacre that took the lives of Veracruz photojournalist Ruben Espinosa, activist Nadia Vera, and three more women.

The owner of the newspaper, Jesus Villanueva Fernandez, lives just next door to the office and said he hid as the 5 am attack took place. Eighteen bullet holes were found on the newspaper's building.

Mexico's National Human Rights Commission condemned the attack and the recent broader uptick in aggressions against journalists in Veracruz, and asked the state prosecutor's office to clarify what happened.

The commission will begin an investigation of its own, by sending a group of inspectors to Poza Rica in the coming days. The group will also assess the authorities' response to the attack.

Reporters in Poza Rica expressed fear and worry over their situation, as they remembered the threats issued by governor Javier Duarte in July, who asked them to "behave."

Villanueva gave a radio interview on Monday, where he said he trusts Duarte's government and asked him for help to resume the newspaper's operations.

"We still have faith. Hopefully [Duarte] will help us, because we suffered a lot of damages. The office is closed, we can't print, and our editors had to go to a cyber cafe to wrap up the edition," Villanueva said.