Mourners in Lebanon have buried dozens killed in twin bombings in the city of Tripoli a day earlier as the country observed a day of national mourning under tight security.

Friday's attack - the deadliest in Lebanon since its 1975-1990 civil war - drew strong condemnation from the international community.

On Saturday, security forces arrested a suspect in connection with the blasts that killed 47 people.

The National News Agency identified the suspect as Sheik Ahmad al-Ghareeb, and said police took him into custody at his home in the Miniyeh region outside Tripoli.

It said al-Ghareeb, who has ties to a Sunni organisation that enjoys good relations with Lebanon's powerful Shia Hezbollah group, appears in surveillance video at the site of one of the explosions.

Meanwhile, soldiers in armoured vehicles patrolled Tripoli, which has been split by strife over Syria's conflict.

Al Jazeera’s Zeina Khodr said anger was at an all-time high in the city.

Syrians split over Syria

While the Lebanese government's official position on Syria is one of neutrality, both Hezbollah and radical Sunni groups in Lebanon have sent fighters into Syria to fight on opposing sides.

There has been no claim of responsibility for the blasts, but people in the city are pointing the finger at the Syrian government and its ally, Hezbollah.

Al-Qaeda's North African branch also blamed Hezbollah for the bombings and threatened vengeance, a US-based intelligence monitoring website reported on Saturday.

Hezbollah in a statement condemned the blasts and expressed solidarity with the victims, saying they were targets of efforts to fan more violence in Lebanon.

"We consider this the completion of an effort to plunge Lebanon into chaos and destruction," the statement said.

The explosions in Tripoli, 70 km away from the capital Beirut, came a week after a huge car bomb killed at least 27 people in a Shia district of Beirut controlled by Hezbollah.

Source: Al Jazeera and agencies