A Hezbollah-led general strike in Lebanon which saw main roads blocked by burning tyres and rubble has turned into an armed riot, with two people killed and 40 injured.

The Shia fundamentalist group blocked dozens of roads all around Beirut this morning in its latest attempt to force Fouad Siniora, the Lebanese Prime Minister, to resign. The main road to the city's international airport was obstructed and several international airlines cancelled flights to and from Beirut, as Hezbollah attempted to grind the country to a halt.

Violent clashes broke out in towns and cities all over central and northern Lebanon between people both in favour of, and against, the Government, in what amounted to the biggest sectarian confrontation between Shia Hezbollah and its Sunni opponents for months.

Police say two people have been killed while 44 others sustained gunshot wounds in clashes. The fatalities were reportedly in Halba and Tripoli, both in the north, but few further details were available this afternoon.

Nicholas Blanford, The Times correspondent in Beirut, witnessed disturbances this morning between Shia Hezbollah supporters and Sunni opponents at a Hezbollah barricade in Beirut.

"There are a bunch of Hezbollah on one side of a broad barricade running between east and west Beirut, and on the other side of the road you have got Sunnis who are throwing stones and rioting," he said.

"The army is trying to intervene - they broke it up intermittently, and are firing shorts in the air, but they cannot stop it and the riots are continuing.

"It is turning into a full scale riot and the situation is deteriorating quickly."

Hezbollah, which is backed by Iran and Syria, called the general strike as a dramatic escalation in its attempt to force the Western-backed Government to stand down.

Protesters, mainly Shia Muslims, piled up rocks and stones to block public highways and prevented anyone from going to work throughout Beirut, while smoke from the burning tyres billowed high into the morning sky.

As the troubled worsened the Lebanese Government brought in the Army to maintain order, at flashpoints all over the country.

The riots come at a particularly damaging time for the Government, as potential donors are due to gather in Paris for a major aid conference on Thursday to help get Lebanon back on its feet after last summer's war between Hezbollah and Israel, which Hezbollah is accused by the West of starting.

Hezbollah has called for the formation of a national unity government, in which it and its allies have a veto.

"It is one of the chapters of the putsch," Marwan Hamadeh, the telecommunications minister, said of the Hezbollah action. "This will fail as in the past, and the legitimate government of Lebanon will remain steadfast."

Since the beginning of December, Hezbollah has been besieging the main government building in Beirut with peaceful demonstrations but, so far, their tactics have not had forced the Government to resign so the Iranian-backed militia launched today's action to step up the pressure.

The 34-day conflict between Hezbollah and Israel, which ran between July 12 and September 6 last year, raised sharp sectarian divides in Lebanon.

Hezbollah is blamed for starting the confrontation by firing Katyusha rockets and mortars at Israeli military positions and border villages in order to divert attention from another Hezbollah unit, which crossed the border, kidnapping two Israeli soldiers and killing three others.

Israel's reprisals, which it claimed was designed to target Hezbollah positions, caused a great deal of damage to the south of the country, much of which is Shia and supports Hezbollah.

The conflict killed over 1,200 people overall, most of whom were Lebanese, severely damaged Lebanese infrastructure, and displaced nearly 975,000 Lebanese and 300,000 Israelis.

After the war came to an end, Hezbollah blamed the Lebanese Government for failing to support it - while the Lebanese Government was reportedly furious with Hezbollah for dragging it into a conflict it had not asked for.