Kieran Doherty, the Irish nationalist hunger striker in British-ruled Ulster who was elected to the Irish parliament in June, died tonight in the Maze Prison outside Belfast after refusing food for 73 days.

Doherty, 25, a member of the Provisional Irish Republican Army serving a 22-year sentence for possession of explosives and firearms in a hijacked car, was the second hunger striker at the Maze to die in less than 48 hours. Eight have now died since May in a protest by convicted Irish nationalist terrorists demanding that prison rules be changed so they would be treated less like criminals.

Because Doherty was elected to the Irish parliament and a by-election will be necessary to replace him, his death is expected to test the magnitude of sympathy for the hunger strike in the Irish Repbulic.

Doherty's death was followed by a continuation of the violence in Northern Ireland that began early yesteday with the death of Kevin Lynch, 25, a member of the Irish National Liberation Army, after 71 days of starvation. Gangs of youths attached policee and Army posts and patrols with bricks and molotov cocktails, according to police. A rocket fired at a British armored personel carrier in Belfast tonight critically injured a soldier.

Earlier today, before Doherty's death, Ulster police officers Andrew Woods, 50, and John Smyth, 34, both married with children, were killed when a 600-pound terrorist bomb exploded underneath their car on a rural road in Tyrone County, near the border with Ireland. Two other police officers escaped without injury in a car just in front of them.

Despite growing pressure from Irish government and church leaders and some of the hunger strikers' relatives, the Provisional IRA said in a statement today that the prisoners have "flatly refused" to end their fast. Two more will take the places of Doherty and Lynch on hunger strike, the Provisional IRA said.

Since their deaths and the decision Firday by the family of Patrick Quinn to authorize medical treatment to try to save his life, five men are currently on the unger strike. Their strikes range from 19 to 56 days. Doherty survived the longest of the eight who have died.

His parents, Alfie and Margaret Doherty were at his bedside in the Maze Prison Hospital when he died at 7:15 p.m. Doherty's father had issued a statement last night attacking attempts by Irish government and religious leaders to persuade relatives of the hunger strikers to help end the protest and save the dying prisoners' lives.

Doherty was able to run for the Irish legislature by taking advantage of citizenship rights offered by Ireland to everyone on the island on both sides of the border. Eight such prisoners in the Maze won surprising support from voters in strongly nationalist, mostly rural areas in Ireland's June national election. Two of them, Doherty and Patrick Agnew, a Maze prisoner who has not joined the hunger strike, were elected to parliamentary seats in multimember rural constituences on the border with Ulster.

An electin will be held late this autumn to fill the seat vacated by Doherty's death in the Cavan-Monaghan constituency. Unless another prisoner runs and wins, which is considered less likely with only a single seat at stake, the opposition Fianna Fail Party of former prime minister Charles Haughey would be favored. This could reduce the already slim three-seat parliamentary majority that put Prime Minister Garret FitzGerald's month-old government in office.

FitzGerald had successfully pressured the British government to be more flexible in seeking a settlement to the hunger strike. But after a violent riot by hunger strike supporters two weeks ago in Dublin, where there is less sympathy for the protest, FitzGerald strongly supported the tough response by police and then blamed the Provisional IRA for thwarting efforts to settle the hunger strike.

Tonight FitzGerald expressed his "sincere sympathy" to Doherty's family, which he has met twice in recent weeks along with other hunger strikers' relatives. But he added, "I have also learned with sorrow of the two constables murdered today in the course of their duty in County Tyrone. This deplorable act brings only further disgrace on the organization which carried it out."