Early findings from the investigation into the Flydubai cockpit stabbing increasingly point to terrorism, a senior US official briefed on the Israeli inquiry and a Saudi official briefed on the investigation told NBC News. Israeli officials allege the co-pilot stabbed Captain Smit Machchhar and tried to crash flight FZ1073 from Dubai to Tel Aviv before passengers and crew subdued him.

The UAE has invited Israel to join the investigation, Israeli Prime Minister Benjamin Netanyahu told CNN, saying it remained unclear whether a state actor played a role. “I spoke to President bin Zayed of the United Arab Emirates, and he agreed immediately that we should join the investigation,” Netanyahu said.

The aircraft landed safely in Tabuk, Saudi Arabia, where authorities arrested and questioned the suspect, Netanyahu said. Passengers later reached Israel on a replacement flight, and India’s embassy reported Machchhar was in stable condition in hospital. Flydubai has suspended flights to and from Israel during the inquiry and said the reasons and motives behind the incident remained unknown.