US President Donald Trump has warned that Iran could face a strong military response if investigators establish that it was connected to an attack on a Flydubai flight travelling from Dubai to Israel.

Trump issued the warning on Thursday as authorities continued investigating an incident in which the co-pilot allegedly attacked the captain, causing the aircraft to lose altitude rapidly before passengers and crew intervened.

The flight, carrying more than 170 people, was eventually diverted to Tabuk in Saudi Arabia, where it landed safely. The co-pilot was detained and later transferred to the United Arab Emirates, where a UAE-led investigation is underway.

Asked whether Iran was involved, Trump said information available to him suggested there could be a connection, although investigations were still ongoing. He said Iran would be “hit very hard” if it was found to be responsible.

Trump did not provide evidence publicly linking Iran to the incident.

Israeli Prime Minister Benjamin Netanyahu has said the Omani co-pilot had undergone what he described as Islamist radical indoctrination and appeared to have attempted to crash the aircraft. Israeli officials have also joined the UAE-led investigation to examine the suspect’s background and possible motive.

The incident began when the co-pilot allegedly attacked the captain in the cockpit. Despite being injured, the captain managed to open the cockpit door, allowing passengers to enter and help restrain the attacker.

A reserve crew member who was travelling on the flight subsequently helped take control of the aircraft before it landed in Saudi Arabia.

The United Arab Emirates is investigating whether the incident was an act of terrorism and whether the suspect acted alone or had links to an organisation or another country.

As of October 2, authorities had not publicly established an Iranian role in the attack. The investigation into the suspect’s motives and possible connections remains ongoing.