Zeina Karam?and Philip Issa

BEIRUT: Multiple bombings struck a government-run checkpoint in the central Syrian city of Homs on Tuesday, killing at least 20 people and wounding over 100 amid intense political jockeying ahead of U.N.-backed peace talks scheduled to begin in Geneva on Friday.

The office of the U.N. envoy for Syria said it sent out invitations for the talks, but with just three days to go, the opposition is still undecided about whether it will attend. One opposition official suggested the Saudi-backed opposition delegation may boycott the talks.

Khawla Mattar, a spokeswoman for Staffan de Mistura, told the Associated Press in Geneva that the envoy would not make public the numbers and identities of the invitees until his office gets “feedback from the invited parties” — a sign of the delicacy of his task.

The talks are meant to start a political process to end the conflict that began in 2011 as a largely peaceful uprising against Assad’s rule but escalated into an all-out war after a harsh state crackdown. The plan calls for cease-fires in parallel to the talks, a new constitution and elections in a year and a half.

The attack in Homs, which was claimed by the Islamic State group, came as government forces retook a southern town from opposition fighters and other militants.

Homs Governor Talal Barazi told the SANA news agency that the checkpoint was hit “first by a car bomb, which was then followed by a suicide bombing.”

Syrian state television broadcast footage of the aftermath of the attack, showing cars ablaze and extensive damage to shops and apartments around the site of the explosion in the Zahra neighborhood, which is inhabited mostly by members of President Bashar Assad’s Alawite sect, an offshoot of Shiite Islam. The district has been a frequent target of bombings in recent months.

The Britain-based Syrian Observatory for Human Rights, an opposition group which relies on a network of informants across Syria, quoted witnesses at the scene as saying the first bomber attracted a crowd of security agents by shouting curses about the Homs governor, then blew up his vehicle.