Two armed Jordanian hijackers of a Kuwaiti jetliner surrendered unconditionally at the airport here and released unharmed 40 persons who had been held captive for more than 24 hours as the plane flew around the Persian Gulf, the Kuwait News Agency said.

Guns, hand grenades and explosives reportedly were confiscated from the hijackers.

Minutes earlier Kuwait's government radio announced the British pilot and copilot had slipped away from the plane and reached safety.The Kuwait Airways jet had landed at the airport earlier yesterday, its third stop here since the hijackers seized it Thursday.

After the two crewmen reached safety, security forces surrounded the plane parked at the end of a runway and said they had it under control, the radio reported.

The aircraft landed here after trying to land in Tehran on flight from Abadan, the oil-refining city in southwestern Iran earlier in the day. It had spent about seven hours on the ground in Abadan before heading to Tehran, Iran state radio reported. The Iranian news agency Pars said Iranian President Abol Hassan Bani-Sadr prohibited their landing and ordered the airport closed.

Pars and Radio Kuwait earlier had reported there were four hijackers.

The hijackers were reported to have threatened to blow up the airliner unless they were paid a debt owed them by a Kuwait merchant. Conflicting reports cited the amount demanded as between $750,000 and $2.7 million.

The Kuwait Airways Boeing 737 was hijacked Thursday on a flight from Beirut to Kuwait. It landed in Kuwait and during a 90-minute stop, the hijackers released 37 women and children on board.

The plane then flew to Bahrain, refueled there, flew back to Kuwait for a second time, then took off for Abadan, 60 miles north of Kuwait across the top of the Persian Gulf and the site of the world's largest oil refinery.