(updated  April 30, 12:10 p.m.)-Authorities have temporarily closed the Masaya Volcano National Park as they continue to monitor an increase in “unusual activity,” the government reports.

In recent hours, the volcano, which has been grumbling off and on for hundreds of years, has emitted an increase of gas and ash and has even shot out several hot rocks, causing a brushfire on the side of the volcano.

The alert was first declared on Saturday, when authorities from the National System of Prevention, Mitigation and Attention to Disasters (SINAPRED) announced they are monitoring the volcano due to the presence of “unusual activity.”

Angélica Muñoz, director of geophysics at the Institute of Territorial Studies (INETER), says authorities have noticed an increase in micro-seismic activity and an increase in gas emissions from the volcano’s Santiago Crater over the past week. She said authorities have also discovered a new fissure near the crater, which is emitting gases and “an unusual noise” that sounds like “an airplane turbine,” according to the Sandinista media.

The government’s media arm reports that President Daniel Ortega has “instructed” Guillermo González, the head of SINAPRED, to intensify vigilance of the volcano.

“We just want the population to be informed about the situation, which we are paying close attention to. But there is no alarm,” González told Ortega’s journalists.

Masaya Volcano—Anastasio Somoza’s old dumping ground for political dissidents— is one of six active volcanoes under constant vigilance in Nicaragua. Since 1520, Masaya Volcano has erupted 18 times, but it was most nettlesome between the years 1772-1820, even after the Spanish dubbed it with the untouristy moniker, “The Gate to Hell.”