By Crispin Thorold
BBC News, Jerusalem
"Fasten your seat belts" - that familiar announcement will now be made a little earlier on all flights into Israel.
Imad Mughniyeh died in a blast in Damascus
The Israeli Transport Ministry has ordered airlines to increase their security. The new guidelines include a requirement that passengers remain seated for the final thirty minutes of flights into Ben Gurion airport.
This is the latest of several security measures that have been introduced by the Israeli government after the killing of one of the leaders of Hezbollah earlier in the month.
Imad Mughniyeh died in an explosion in a suburb of Damascus on February 12th. Hezbollah and the Syrian government immediately blamed Israel for the killing. During Imad Mughniyeh's funeral the leader of Hezbollah, Hassan Nasrallah, promised to avenge his death.
"Zionists, if you want this sort of open war, then let the whole world hear, so be it!", Hassan Nasrallah declared. The Hezbollah leader said that Israel thought that Mughniyeh's death "would lead to the destruction of the resistance... but they are wrong".
The Israeli government has denied any involvement in the apparent assassination, but acknowledges that the risk to Israelis and other Jews around the world has increased.
"Hezbollah has repeatedly blamed Israel for the death of Imad Mughniyeh," said a statement from the prime minister's office. "[This] increases the danger of its terrorist threats against Israeli targets abroad."
Patriot air defence missiles have been deployed near the city of Haifa, which was bombarded with rockets during the war between Hezbollah and Israel in 2006. Israel is "prepared on all fronts", said Defence Minister Ehud Barak.
Patriot air defence missiles have been deployed to deter any attack
The National Security Council's Counter-Terrorism Bureau has recommended that Israelis travelling abroad avoid places where there is a high concentration of Israelis.
Business people and tourists have once again been warned about the potential kidnapping of Israelis abroad, mainly in countries with Arab or Muslim links.
Israeli ministers travelling overseas will now have bodyguards at all times, even during private visits. Israeli embassies have also been put on high alert.
In the United States, the Federal Bureau of Investigation has told local police to watch for potential attacks by Hezbollah within North America, against Jewish and Israeli interests.
"While retaliation in the US homeland is unlikely, Hezbollah has demonstrated a capability to respond outside the Middle East to similar events in the past," said an intelligence bulletin quoted in the Los Angeles Times.
This substantial increase of security in Israel and worldwide has a precedent. In February 1992 Hezbollah leader Sheikh Abbas Al-Musawi was killed by an Israeli helicopter strike on his convoy in southern Lebanon.
In the months that followed Hezbollah launched attacks against Israel, Israelis abroad and Jewish interests worldwide. For five days Katushya rockets were fired into Israel. A diplomat was killed in Turkey.
Then there were two attacks in Buenos Aires: in 1992 the Israeli embassy was bombed, killing 29 people and an explosion at a Jewish community centre in 1994 left 85 civilians dead.
Imad Mughniyeh is suspected of having a hand in the attacks.