Two hostages aboard a hijacked jumbo jet broadcast messages Friday saying they would be killed if the Kuwaiti government did not bend to the demands of the Arab gunmen holding the plane.

About 30 passengers were reported being held in grim conditions, all handcuffed and forced to remain silent. About four crew members also are believed to be aboard the jet.The Kuwait Airways Boeing 747 was hijacked April 5 on a flight from Bangkok to Kuwait with 112 people aboard. It was forced to land at Mashhad in northeastern Iran, where the hijackers freed 57 hostages.

The plane then flew on to Larnaca, Cyprus, where 13 people were released and two Kuwaitis were killed. It arrived in Algiers Tuesday night.

The hijackers are demanding that Kuwait release 17 jailed pro-Iranian terrorists. Kuwaiti officials have refused.

The two recorded messages, almost identical in wording, were sent by radio from the plane to the control tower at Houari Boumedienne Airport.

"In the name of God the merciful, I greet my family and my friends and I ask the Kuwaiti authorities to free the 17 prisoners held in Kuwaiti prisons," said Soleiman Mohammed Soleiman al-Mashari. "In the event of refusal, they are going to kill us."

In a second message, a man identifying himself as Mohammed Ahmed Al-Ajem said: "I am one of the hostages from the Boeing . . . and I ask the Kuwaiti authorities to free the prisoners held in the prisons. Without that, the kidnappers have decided to kill us."

A passenger made a similar plea Thursday.

The hijackers released one of their captives Thursday during the second day of negotiations here with a Kuwaiti delegation through Algerian mediators.

The freed hostage, Djuma Abdal-lah Chatti of Kuwait, is a 70-year-old diabetic who doctors said urgently needed an insulin shot.

The gunmen issued a statement saying they would not budge in their demand that the 17 prisoners be released. They said they stood by their demand "even if the price we have to pay is very high."

"We are not highway bandits," they said in the statement, radioed to the control tower in Arabic and English. "We are men of principle."

According to a Kuwaiti official who spoke on condition of anonymity, Chatti reported that the hostage worst affected was Fadel Al-Sabah, 33, cousin of the emir of Kuwait, regarded as the hijackers' most valuable captive. Al-Sabah's two sisters also are on board.

Chatti was quoted as saying Al-Sabah suffered from a severe nervous disorder even before he boarded the plane, and the experience of the hijack "seems to have put him over the brink."

Al-Sabah had continuous violent shakes, could not speak and "just cries all the time," he said.

Chatti said there were eight hijackers. Other freed passengers have said there were between five and eight.

"Praise to God, I am fine, but they had me tied all the time and I am tired," Chatti told reporters in the airport lounge. "They are not good people. They beat me."