Beirut - Dozens of pro-Syrian opposition followers Wednesday blocked roads leading to Beirut, a few hours before a scheduled protest by Lebanon's main labour union was due to start.

Burning tyres and sand blocked the main highways leading to the capital and were blocked by followers of the Lebanese Shiite movement Hezbollah and its ally Amal, to prevent people from reaching the capital.

Army soldiers and police were on full alert and managed to open some of the blocked roads, but the airport thoroughfare was still obstructed by burning tyres.

"This is only a start," said an opposition follower who was near the airport.

The blockade came just hours before a scheduled demonstration by Lebanon's top labour union to protest the high cost of living.

Lebanon is passing through its worst political crisis since its 1975-1990 civil war. Hezbollah, who is leading the opposition, has been engaged in a campaign against Prime Minister Fouad Seniora's government since November 2006. The standoff has left Lebanon without a president for five months.

The Syrian-backed opposition has urged supporters to back the strike by Lebanon's main labour union.

On Tuesday, the Western-backed government accused Hezbollah of violating Lebanon's sovereignty by operating its own communications network and installing spy cameras at Beirut airport.

The government, supported by the United States and a number of Arab countries including Saudi Arabia, also removed the head of Beirut airport security in another challenge to Hezbollah, which is backed by Iran and Syria.

Hezbollah said the communications network was part of its security apparatus and its ongoing fight against Israel. (dpa)