Gunmen belonging to a nationalist group that seized a police station in remote southern Peru (search) ambushed a police vehicle responding to the scene Sunday, killing four officers and wounding several more, hospital officials said.

One gunman was gravely wounded.

The shooting started before dawn on a bridge on the other side of town from the captured police station in Andahuaylas, 275 miles southeast of Lima, Radioprogramas radio reported. The station was seized Saturday by followers of Antauro Humala (search), a retired army major who, along with his brother, seeks to establish a nationalist indigenous movement modeled on the ancient Incan Empire.

The attackers demanded the resignation of President Alejandro Toledo (search). At least seven people were wounded in a shootout during the takeover early Saturday and brought to Lima.

"This is a military protest and we are willing to lay down our arms and surrender when Toledo resigns from office," Antauro Humala told Radioprogramas Radio from the captured police station in Andahuaylas on Saturday.

Toledo, who refused that demand, declared a 30-day state of emergency in the remote Andean province. He cut short a holiday trip to convene a Cabinet meeting on the crisis.

A state of emergency suspends basic constitutional rights such as freedom of assembly, permits authorities to enter homes without search warrants and authorizes the president to charge the armed forces with maintaining order.

Officials at two hospitals told Peruvian media the death toll from Sunday's ambush included a police captain, lieutenant and two officers.

"This was the result of an ambush of a vehicle that was on the colonial bridge of Andahuaylas heading to the airport, where three police died, a captain and two officers, all hit by bullets," Dr. Luis Altamirano, director of the state-run Hospital of Essalud in Andahuaylas, told Canal N television.

Altamirano also said the hospital received three wounded victims.

Dr. Leonides Mayma of the town's general hospital told Radioprogramas that a police lieutenant brought there was dead on arrival. He said his hospital also was treating a gravely wounded follower of Humala.

Prime Minister Carlos Ferrero said Humala and less than 100 of his followers, most of them army reservists, seized the police station Saturday after the police commander there refused to sell them weapons.

Humala is the brother of Ollanta Humala, an army commander stationed in South Korea whom the government retired last week.

In October 2000, Lt. Col. Ollanta Humala and his brother led 50 followers in a short-lived military uprising, a month before the collapse of former President Alberto Fujimori's corruption-ridden, 10-year regime. Antauro Humala had been forced to retire from the army three years earlier.

The revolt failed to spark the wider rebellion the brothers had hoped for in barracks across the nation to establish their nationalist indigenous movement.

Peru's Congress granted the brothers and their followers amnesty in December 2000.

While Ollanta Humala was transferred for overseas duty, Antauro Humala forged a small, but vocal, political movement in his brother's name that has accused Toledo of selling out Peru to business interests in Chile, a historic rival.

Ollanta Humala said in a telephone interview with Radioprogramas he was still in Seoul and that the military was delaying his departure with administrative matters.

Toledo, who took office in July 2001 with a popularity rating of nearly 60 percent, has tried to disassociate himself from a series of corruption scandals during the past year involving relatives and Cabinet ministers. His approval rating hovers at about 9 percent.