Russia's foreign ministry on Friday called on all sides in Lebanon to "show restraint" after deadly clashes rocked a Beirut suburb as tensions rise over last year's port explosion.

Seven people were killed and dozens wounded on Thursday when violence erupted following a rally by Hizbullah and Amal Movement protesters demanding the removal of the judge investigating last August's blast that left at least 210 people dead.

Lebanon prepared to bury the victims of its deadliest sectarian unrest in years Friday after gunfire gripped the Tayyouneh-Ain el-Rummaneh area for hours and revived the ghosts of the civil war.

Seven people were killed and dozens wounded Thursday when violence erupted following a rally by Hizbullah and Amal Movement protesters demanding the removal of the judge investigating last year's port blast.

Schools, banks and government offices across Lebanon shut down Friday after hours of gun battles between armed groups killed seven people and terrorized the residents of Beirut and its suburbs.

The government called for a day of mourning following the armed clashes, in which gunmen used automatic weapons and rocket-propelled grenades on the streets of the capital's edge and suburbs, echoing the nation's darkest era of the 1975-90 civil war. The gun battles raised the specter of a return to sectarian violence in a country already struggling through one of the world's worst economic crises of the past 150 years.

Hizbullah and Amal on Thursday openly accused the Lebanese Forces of launching an “armed attack” on their supporters in the Tayyouneh area, which had during the day witnessed hours-long armed clashes reminiscent of the beginning of the 1975-1990 civil war.

The United States on Thursday urged an easing of tensions in Lebanon after deadly violence in a Beirut suburb sparked fears of a return to sectarian strife.

U.N. Special Coordinator for Lebanon Joanna Wronecka expressed "deep concern" Thursday over the outbreaks of violence that took place in and around Tayyouneh and resulted in several deaths and injuries.

Condemning the "use of armed violence outside of state authority," she underscored the need for restraint and for maintaining calm and stability and ensuring the protection of civilians.

Tarek Bitar, the young and discreet judge investigating last year's devastating Beirut port explosion, is arguably the most exposed man in the country.

France on Thursday expressed concern over the deadly unrest that erupted in Lebanon over the investigation into last year's Beirut port blast and urged all parties to calm the situation.

With gun battles breaking out in Tayyouneh Thursday during a protest against Judge Tarek Bitar, AFP looks at how the apocalyptic blast that devastated the port of Beirut last year has rocked the country.

Amal Movement and Hizbullah accused "armed and organized groups" of assaulting their supporters in Tayyouneh, in a joint statement Thursday.