Lebanon on Monday received emergency medical supplies to equip its hospitals for possible war injuries and Beirut airport was teeming with people trying to leave the country amid fears a full-scale conflict was on the horizon.

Tensions in the region have spiralled in the last week following the killing in Tehran of Palestinian militant group Hamas' head, and an Israeli strike on Beirut's suburbs that killed a top commander in Lebanon's armed group Hezbollah.

Hezbollah and Iran have vowed to retaliate against Israel for the killings, prompting concerns that the multiple fronts being fought in parallel to the Gaza War could escalate into a full-blown regional war.

Hospitals in southern Lebanon, where most of the tit-for-tat exchanges between Hezbollah and the Israeli military have taken place, are worn down by a years-long economic meltdown and have struggled to cope with wounded patients over the last 10 months.

On Monday, the World Health Organization delivered 32 tons of medical supplies to Lebanon's health ministry, including at least 1,000 trauma kits to treat possible war wounded.

"The goal is to get these supplies and medicines to various hospitals and to the health sector in Lebanon, especially in the places most exposed (to hostilities) so that we can be ready to deal with any emergency," health minister Firass Abiad told reporters at the airport landing strip where the aid arrived.

In the airport's departure hall, families of Lebanese origin who had come to their homeland for the summer lined up to check in to their departing flights, sad to be leaving earlier than expected.

Countries including France, Britain, Italy, Turkey and others have urged their nationals to leave Lebanon as long as commercial flights are still available.

"It is just very sad, oh God, the situation is really sad. We get out of a crisis, we go into another one," said Sherin Malah, a Lebanese citizen living in Italy who had come to Lebanon to visit her mother and was heading home early.

The United States has urged its citizens who want to leave Lebanon "to book any ticket available," while the United Nations has asked the families of its staff to leave Lebanon and the Swedish embassy has temporarily relocated its staff to Cyprus.

But others in Lebanon appeared more relaxed. Along the sandy coastline of Lebanon's port city of Tyre, about 20 km (12 miles)from the border with Israel, children splashed in the water as plumes of black smoke from Israeli shelling further south curled up from the hills behind them.

"As for the current situation, as you can see, all the people are by the beach, this land is our land, and we will not leave it," said Tyre resident Ghalib Badawy.