"If the Israeli massacres continue, we will continue our operations," Abdul Malik al-Houthi said in a televised speech.
The experts pointed to an email, seen by Reuters, from the group postponing a planned security briefing that had been due to take place in the coming days as a possible signal.
The maritime demarcation agreement would be in line with international law and would allow two countries to determine authorities for oil and hydrocarbon exploration.
Israeli companies showcase advanced naval tech at Euronaval following court victory in France.
Its hull carries slogans reading: "Free Palestine," "Gaza you are not alone" and "Stop the Genocide," while its humanitarian aid cargo consists mostly of medicines.
The missing crew member was suspected to be trapped in the engine room, maritime sources said. The rest of the crew were "safe and sound" and had adequate food supplies, Cacdac said.
Ambrey said a radio communication indicated the vessel was hit by a missile and that there was a fire onboard.
In March, the group's leader said the group was expanding its attack area to prevent Israel-linked ships from passing through the Indian Ocean toward the Cape of Good Hope.
The tanker, which was not identified by name, was en route from Pimorsk, Russia, to Vadinar, India, when it was attacked, Ambrey said in its advisory note.
Last week the Houthis's leader warned that the group would begin attacking ships heading toward the Cape of Good Hope in Africa's southern tip.