GEORGETOWN, Guyana (AP) — Gunmen killed 12 people, including three police officers, in a Sunday night assault on a small town in Guyana, authorities said. It was the second major attack blamed on gangs in recent weeks.Police said men dressed in military fatigues and armed with assault rifles invaded a police station and made off with ammunition and weapons in the southwestern township of Bartica.The nine civilians included five people who were sleeping in hammocks along the Essequibo River outside the police station, Health Minister Leslie Ramsammy."This is the work of brutish beasts. This is more than horrific, "Ramsammy said.At least seven civilians were wounded, including one man in critical condition, said Lester Valentine, a doctor at the Bartica hospital.Police Cmdr. Gavin Primo said the gunmen broke into a strong box and took away guns and ammunition. Valentine said the man entered the town by boat and fired indiscriminately for about an hour while people hid in their homes.Bartica is a bustling town of about 15,000 people where miners buy supplies before heading into the South American country's interior to look for gold and diamonds.People in the town said some the gunmen also fired on businesses, including the main hotel."This is just terrible, just awful," said hotelier Stephen Bell, who lives a block away from the Bartica police station. "Not a man is on the street. The area is deserted."The attack came just three weeks after gunmen attacked the coastal village of Lusignan, killing six adults and five children.Alleged gang leader Rondell Rawlins — the country's most-wanted man, who is implicated in the 2006 assassination of Agriculture Minister Satyadeo Sawh — has claimed responsibility for the Jan. 26 killings. He had threatened more deadly assaults if his pregnant girlfriend, missing since around Jan. 18, is not returned.Authorities issued an arrest warrant last week for a suspected underworld figure they believe kidnapped her.President Bharrat Jagdeo's administration has called Rawlins' gang domestic terrorists intent on creating mayhem in this English-speaking South American nation of 730,000.Security forces have offered a $250,000 reward for information leading to Rawlins' capture.The Lusignan massacre sparked protests by villagers over Guyana's failure to prevent gang violence. Police and soldiers have since arrested or killed people they alleged members of Rawlins' gang. No charges have been filed, however.