Tension in Lebanon has reached a fever pitch as the international tribunal investigating the assassination of former prime minister Rafik Hariri in 2005 delivered its indictments to the International Criminal Court in Hague on Monday.

Last week, Hizbollah toppled the Lebanese government when it led a walkout of ministers from the administration headed by Saad Hariri, the assassinated PM's son. They were protesting against the government's co-operation with the tribunal.

It is believed that senior Hizbollah operatives have been indicted for carrying out the assassination. Hizbollah has claimed that the tribunal is part of a "Zionist plot" and that Israel was behind Mr Hariri's death.

Following Mr Hariri's refusal to renounce the tribunal, Hizbollah leader Sheik Hassan Nasrallah warned of "significant political changes in Lebanon".

According to reports in Arab newspapers, Hizbollah recently carried out a mock exercise in which it practised taking control of the capital Beirut.

Hizbollah is trying to show Hariri ‘who is the boss'

The exercise included a takeover of the city's international airport and sea port, and took place in the early hours of Tuesday morning.

In addition to Hizbollah fighters, members of the other Shia movement Amal are reported to have taken part in the exercise.

IDF Chief of Staff Lieutenant General Gabi Ashkenazi warned a month ago that Hizbollah could take over the country in a day and that it had already influenced units in the national Lebanese army.

Despite these warnings, most Israeli intelligence analysts believe that Hizbollah will not step over the brink and is simply trying to "show Hariri who is boss".

The Israeli defence establishment currently does not believe that Hizbollah will use the tension as a pretext to attack Israel as it could cause another war that would be very unpopular in Lebanon.

In addition, it is believed that Hizbollah's Iranian patrons are interested in maintaining the militant group's long-range missile capability as a threat against a strike by Israel on its nuclear installations, and would not risk a premature war in which Israel would have a pretext to destroy these missiles.

Mr Hariri is currently the head of an interim government but he is incapable of forming a new coalition without the parties that supported the Hizbollah walkout.

Saudi Arabia has tried to broker an agreement between the two sides whereby the Lebanese government would stop co-operating with the tribunal and Hizbollah would allow a new government to form, but neither side was willing to compromise.

Saudi Foreign Minister Saud Al-Faisal said on Wednesday that the situation in Lebanon is "dangerous."