Lebanon’s army on Saturday attempted to restore order after four days of heavy sectarian and factional fighting, during which the opposition Shia Hizbollah movement seized control over most Sunni Muslim neighbourhoods of the capital Beirut.

Hizbollah and its allies said they had started withdrawing their fighters from Beirut. But Saturday nevertheless saw some of the most serious fighting in terms of casualties, with some 20 people reported dead in clashes in the capital and other parts of the country.

The army command agreed to suspend and review two government decisions that had sparked the worst sectarian violence in Lebanon since the 1975-90 civil war and which Hizbollah said had amounted to a “declaration of war”.

The suspension of these measures means that the head of security at Beirut airport – whom the government replaced for allegedly being close to Hizbollah – will remain in his post.

The army also said it would investigate Hizbollah’s dedicated communications network, which the government had declared illegal, in a way ”that would not harm public interest and the security of the resistance”.

The suspension of the decisions is a heavy blow to the prestige of the western-backed government. But one opposition leader said it did no go far enough and called for the measures to be revoked completely.

Hizbollah and its allies would withdraw their fighters from the streets of the capital. But the opposition would continue its campaign of “civil disobedience”, meaning that the road to the airport as well as other routes would blocked.

However, armed fighters remained visible in some parts of west Beirut late on Saturday. Most of the population stayed indoors and many streets bore the scars of heavy fighting.

Earlier in the day, Fouad Siniora, the country’s besieged western-backed prime minister, had in a defiant televised address urged the military to restore order.

”I call on the army to impose security on everyone in all areas and to clear armed elements from the street immediately,” he said.

The country’s fragile army, deeply riven by sectarian differences, stood aside last week as Hizbollah fighters and their allies overran most pro-government Sunni strongholds in the capital.

But late on Saturday, the army deployed in force in some flashpoint areas in Beirut.

Commandos and armoured vehicles were present in the mixed Tariq Jedideh neighbourhood, where earlier in the day at least two people were killed when a Shia man opened fire on a Sunni funeral procession.

Fighting also intensified in the north of the country, a bastion of the pro-government Future movement, where 12 people were reported dead.

In a potentially explosive development, Hizbollah accused fighters loyal to Walid Jumblat, the pro-government Druze leader, of having kidnapped three of its members and killing two of them in the town of Aley in the Shouf mountains.

The confrontation between the government and the opposition, which is led by the pro-Iranian and pro-Syrian Hizbollah, goes back more than 18 months and has kept the country without a president since last October.

Mr Siniora criticised Hizbollah, accusing it of having staged a coup. He called for a minute’s silence at noon on Sunday to commemorate those killed over the last four days. The death toll now stands at least at 37.