CAIRO — Arab League chief Nabil Elaraby on Sunday urged Lebanon's Shiite militant Hezbollah to stop fighting alongside government forces in Syria's civil war, after two rockets hit a Shi'ite Muslim district of Beirut.

Sunday's rocket attack was the first to apparently target Hezbollah's stronghold in the south of the Lebanese capital since the outbreak of the two-year conflict in neighbouring Syria, which has heightened Lebanon's own sectarian tensions.

Hezbollah leader Sayyed Hassan Nasrallah declared on Saturday that his heavily armed fighters were committed to the conflict against what he called radical Sunni Islamist rebels in Syria, whatever the cost.

Elaraby strongly condemned Sunday's attacks as well the ongoing clashes in Lebanon's northern city of Tripoli between factions supporting opposing sides in Syria, which have left 25 people dead in the last week.

"[Elaraby] urged the leaders of Hezbollah to reconsider their stance and not get involved in the killing in Syria, stressing that the only way to protect Lebanon . . . is to protect Lebanon's internal unity," the Arab League said in a statement.

"This criminal incident, in addition to ongoing armed clashes in the city of Tripoli, are unacceptable destructive acts that aim to stoke the fire of sectarianism, provoke reactions and upset security in Lebanon," added the statement on the league's website, quoting Elaraby.

In Sunday's attack, one rocket landed in a car sales yard next to a busy road junction in south Beirut and the other struck an apartment several hundred meters away, wounding five people, residents said.

Lebanese authorities, haunted by Lebanon's own 1975-1990 civil war and torn by the same sectarian rifts as Syria, have pursued a policy of "dissociation" from the Syrian turmoil.

But they are unable to stem the flow into Syria of Sunni Muslim gunmen who support the rebels and Hezbollah fighters who back President Bashar al-Assad, and have struggled to absorb nearly half a million refugees coming the other way.