By John Davison
BEIRUT (Reuters) - Lebanese Prime Minister Tammam Salam held an emergency meeting with his security cabinet and military chiefs on Friday as the nation mourned 44 people killed in a double suicide bombing claimed by Islamic State.
The blasts late on Thursday hit a residential and commercial area in a southern suburb of Beirut, a stronghold of Shi'ite Muslim group Hezbollah, in the latest spillover of violence from the war in neighbouring Syria.
The first attacks in more than a year on a Hezbollah bastion inside Lebanon came at time when the group is stepping up its involvement in Syria's civil war, now in its fifth year.
Iran-backed Hezbollah has sent troops over the border to support Syrian President Bashar al-Assad against Sunni Muslim insurgent groups including Islamic State.
Lebanon is also suffering from its own political crisis in which disputes between parties, factions and sects have stopped the government taking basic decisions and left the country without a president for 17 months.
The army established a heavy security presence around the scene of the blast, which on Friday was still littered with debris, damaged cars and motorbikes and shattered glass.
Medical sources raised the death toll on Friday from 43 to 44, with more than 200 people wounded.
Funerals were held in Beirut for several of the victims later in the day, with coffins draped in the flags of Hezbollah and Amal, another Shi'ite movement.
Defence Minister Samir Moqbel said the armed forces were on high alert across the country, and trying their best to keep a fragile calm.
"To tell you the security forces can control things like that 100 percent of the time, I'd be lying," he said.
"We're doing our best in coordination with all the parties on the ground."
Ministers have urged politicians to put all rivalries aside and work towards electing a president and bolstering the government and parliament. State institutions are paralysed by political deadlock.
Beirut residents expressed concern after the violence, saying it raised the spectre of civil strife.
"It's been a year... with no explosions. We thought we were done with this, but were proved wrong yesterday," said central Beirut resident Rajaa, who gave only her first name.
"This explosion targeted Lebanon as whole, not only Beirut's southern suburbs," she said.
Hezbollah warned on Thursday of a "long war" against its enemies.
U.N. Secretary General Ban Ki-moon urged Lebanon's security services and state institutions "not to allow this despicable act to destroy the relative calm that has prevailed in the country over the past year."
The White House pledged to support the country as it worked to "bring those responsible for this attack to justice".
Hezbollah's political opponents in Lebanon, including Sunni politicians, also condemned the attacks.
Syria's civil war is increasingly playing out as a proxy battle between regional rivals, including Iran and Saudi Arabia which support opposing sides in the conflict. The two adversaries also back opposing political forces in Lebanon.
Lawmakers convened in Beirut for a second day on Friday in the first legislative session for more than a year. The meeting aims to pass urgent financial laws to keep the state afloat, but is avoiding thorny political issues.
(Additional reporting by Issam Abdallah, Ahmad Kurdi, Walid Saleh and Hassan Abdallah; Editing by Ralph Boulton)