The Shiite guerrilla group Hezbollah paraded its army in a massive show of strength to counter international calls to disarm, while its fiery leader backed Syria in the face of intense pressure over the U.N. probe into the assassination of a former Lebanese prime minister.

As tens of thousands of flag-waving supporters cheered and applauded, more than 6,000 guerrillas in black, olive and green military uniforms and fatigues marched in formation through Hezbollah's south Beirut (search) stronghold. None were seen to be carrying weapons.

The Shiite Muslim Hezbollah (search), which is supported by Iran, holds the parade every year to mark Jerusalem Day — which calls for the return of the city to Arabs.

But this year's parade came amid heightened tension in Lebanon following Western pressure on Syria to cooperate with a U.N. probe into the assassination in February of former Prime Minister Rafik Hariri (search).

It also followed a U.N. report that Lebanon has made little headway in implementing a resolution demanding the disarmament of Lebanese and non-Lebanese militias, including Hezbollah. That report also calls for Lebanese troops to deploy in southern Lebanon to end Hezbollah's armed presence there.

As part of an effort to prevent a larger regional crisis stemming from the U.N. investigation into the Hariri killing, Egyptian President Hosni Mubarak (search) visited Syria briefly on Friday.

Although details were not released, Mubarak was believed to have talked to Syrian President Bashar Assad about efforts to impose sanctions on Syria if it fails to cooperate with the U.N. investigation, Egypt's Middle East News Agency said.

Hezbollah's show of force was also seen as a sign the group may be trying to strengthen its role in Lebanon following the withdrawal of Syrian troops in April following the Hariri killing. The guerrilla group is represented in Parliament and in the Cabinet.

Hezbollah's leader Sheik Hassan Nasrallah (search) lashed out at U.N. efforts to disarm his guerrillas and accused the international community of serving U.S. and Israeli interests.

"Syria is being punished because it stood by Lebanon," the cleric told the rally. "And because it stood by the Palestinians."

He added that Hezbollah stood "on the side of Syria's leadership and people as it is being targeted by American and Zionist attempts to punish it."

Although the Lebanese government condoned Hezbollah's display, it has been playing tough with pro-Syrian Palestinian militants in recent days. Prime Minister Fuad Saniora did not attend the rally.

Hundreds of Lebanese troops have in recent days surrounded bases near the Syrian border that belong to the pro-Syrian Popular Front for the Liberation of Palestine-General Command and Fatah Uprising groups.

The government indicated Friday that it wished to avoid a military confrontation and troops allowed villagers to supply the bases with food.

"The army's weapons will not be used in the interior against anyone," Defense Minister Elias Murr told reporters.

Islamic Jihad, another pro-Syrian, anti-Israeli group that receives Iranian funding and has offices in Damascus, came under fire in a statement from the Russian Foreign Ministry on Friday.

Moscow said Syria should "take swift measures" to close Islamic Jihad offices "to prevent the use of its territory by armed groups becoming involved in terrorist acts."

The Russians said they were speaking on behalf of the Quartet — themselves, the United States, the European Union and the United Nations — which has developed a so-called "road map" for reaching a full peace agreement between Israel and the Palestinians.

"The Quartet encourages and resolutely supports efforts of the Palestinian Authority to adopt swift measures aimed at preventing illegal and unlawful actions by armed gangs, and also actions directed against the Palestinian Authority," the statement said.