Israeli Prime Minister Benjamin Netanyahu said Thursday that the Omani co-pilot accused of trying to crash a FlyDubai flight to Israel had undergone “Islamist radical indoctrination,” while cautioning that investigators have not yet determined whether he had ties to Iran or other foreign actors or was acting alone.

The comments came a day after the co-pilot stabbed the captain of the Dubai-to-Tel Aviv flight, sending the aircraft into a rapid descent before passengers and crew subdued him. The flight was carrying 174 people.

Netanyahu, speaking to “Fox and Friends” on Thursday, said investigations are still ongoing, but that information about the attacker’s background found that he had been radicalized. He also said the attacker appeared to have been suicidal, pointing to his alleged calls for the crew to kill him after he was subdued.

“This attacker, he calls out to the aircrew, ‘Kill me, kill me!’ So it’s clear he was suicidal,” Netanyahu said. “It looks very likely that he was going to down the plane, and with all the passengers in there, and if you couple that with … Islamist tendencies and radicalization that are found in his background, I think that’ll give us a pretty good clue, but again, I don’t make final conclusions yet.”

Netanyahu confirmed the attacker was an Omani national, which he acknowledged raises questions about how the assailant was able to serve as a co-pilot on a flight carrying Israeli passengers despite Israel’s restrictions involving pilots from countries that do not have diplomatic relations with Jerusalem.

“We have constraints that say you can’t have pilots from countries that don’t have diplomatic relations with Israel. So obviously, he was able to go through that. So there’s a loophole there,” Netanyahu said, vowing to increase security measures.

Netanyahu stopped short, however, of linking the attack to Iran, saying investigators would need more time to determine whether the attacker had outside connections. Israeli officials have said the investigation remains ongoing, while initial assessments indicated the attacker was likely acting alone.

“We’re looking into that, so I can’t draw conclusions yet,” Netanyahu said. “I think it’s too early to say whether he had any connections with Iran or with anyone else … I think we’ll be able to say definitively within a matter of days.”

Netanyahu said the investigations are taking place with the “full cooperation” of the United Arab Emirates. He noted that Israeli authorities had screened the backgrounds of pilots who transported Israeli passengers from Saudi Arabia to Israel following the incident.

The circumstances that allowed the attacker to bring a weapon into the cockpit also remain unclear. Netanyahu said investigators were examining whether pilots are subject to the same metal detector screening as passengers or whether the attacker could have obtained a weapon from the aircraft itself.

“There are two possibilities: one that he didn’t go through a metal detector, because you know passengers go through a metal detector, but I’m not sure that pilots always do,” Netanyahu said. “And then he could have carried a knife, or an ax, or he might have gotten an ax from the equipment in the — you know, that might be standard on this airplane.”