JERUSALEM / GAZA -- Twelve US F-22 stealth fighter jets landed at an Israeli air force base in southern Israel on Monday as part of Washington's military buildup in the Middle East against Iran, an Israeli security official told Xinhua.

The fifth-generation aircraft were seen in video footage departing Britain earlier in the day en route to Israel.

The official said the Israeli military has been preparing for all scenarios, including a possible "Iranian attack or retaliatory strike."

Meanwhile, he said the security establishment assesses the ongoing US-Iran indirect negotiations as "genuine."

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The deployment comes amid a huge US military buildup near Iran and reports that US President Donald Trump was considering launching an initial strike on Iran.

Also on Tuesday, Israel updated its guidelines on what constitutes "essential sectors" in the event of a future state of emergency, drawing on lessons from last summer's 12-day war with Iran, during which missile and drone attacks disrupted daily life in many parts of the country and prompted widespread security alerts.

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Under the revised regulations, employees in key industries, including communications, cyber infrastructure, medical technology and energy, could be required to continue working even if a state of emergency is declared, according to a report by state-owned Kan TV.

‘2 Palestinians killed in N. Gaza Strip’

Two Palestinians were killed Tuesday by Israeli fire in the town of Beit Lahia in the northern Gaza Strip, according to Palestinian sources.

The bodies of the two men were transported to Al-Shifa Hospital in Gaza City, according to medical sources.

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Also on Tuesday, the Palestinian Red Crescent Society (PRCS) announced the launch of a logistical operation to deliver vital medical supplies from its warehouses in the West Bank to the Gaza Strip via the Israeli-controlled Kerem Shalom crossing.

Five trucks carrying more than three million units of medicines and medical solutions departed on Monday, the society said, with four more scheduled to follow.

The convoy was organized through months of coordination with the International Committee of the Red Cross and funded by international partners, the PRCS added, noting that the aid is essential to ensuring emergency health services to citizens amid severe strain on Gaza's health sector.