Funerals are being held for the 47 people who were killed in twin explosions in the northern Lebanese city of Tripoli.

Mourners buried dozens killed in coordinated bombings outside two Sunni Muslim mosques as the country observed a day of national mourning on Saturday under heavy security.

Soldiers in armoured vehicles patrolled the tense city, which has been split by strife over Syria's conflict.

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

Friday's bombing - the deadliest attack in Lebanon since the country’s 1975-1990 civil war - left also more than 500 wounded.

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 but people in the city are pointing the finger at the Syrian government and its ally in Lebanon, the Shia armed group Hezbollah.

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

"That vile party ... should know that it will meet retribution soon," al-Qaeda in the Islamic Maghreb (AQIM) said, according to the SITE monitoring service.

Hezbollah previously released a statement condemning the blasts and expressing 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.

Hezbollah has openly declared its support for Syria's President Bashar al-Assad. On the other hand, a number of Lebanese from Tripoli have gone to Syria to fight with the armed opposition.

Source: Al Jazeera and agencies