BANGKOK (AP) — Thai police said they arrested three men identified as Chinese citizens who were shot as they tried to rob a gun shop in Bangkok on Friday. A fourth suspect was arrested later.

The men entered the shop near Bangkok's Chinatown armed with BB guns and knives, said police Col. Suriya Jamningchoke.

He said the men used the knives to attack the shop owner and his assistant, who shot at the suspects in self-defense. The men were later shot by officers patrolling the area, police said. A fourth member of the gang escaped but was later tracked down and arrested, Suriya said.

Police were searching for a fifth man who is believed to be their "boss," said police chief Chakthip Chaijinda, adding that the men did not disclose the purpose of the robbery.

"They said they needed to get the guns first before their boss would say what to do with them," Chakthip told reporters. He said it was too soon to say if they were planning an attack.

"We can't say for sure yet because we haven't found their boss yet. They were just following orders," the police chief said. "I believe they didn't want to steal the guns just to resell them."

Chakthip said police found the men's passports, which were from China, and said they spoke Chinese and no Thai.

The attempted robbery occurred in a neighborhood that has dozens of shops selling guns.