Main news of March 4

A roundup of what has happened in the past 24 hours

WORLD

* Forces loyal to Libyan President Mammar Gaddafi killed at least 30 civilians when they tried to retake the rebel-held town of Az Zawiyah, Al Jazeera said

* Egypt will hold a national referendum on amendments to its constitution on March 19, the Egyptian government said

* London Mayor Boris Johnson and Russian businessman Mikhail Prokhorov met in City Hall in the British capital for the launch a Russian cultural festival

* Forces loyal to Libyan dictator Muammar Gaddafi are preventing 12,500 refugees from crossing the heavily-armed border between Libya and Tunisia, the UN refugee agency said

* Thousands of people gathered on Baghdad's Tahrir Square for an anti-government demonstration

* Tunisia's interim leader Fouad Mebazaa announced that nationwide polls to elect a constitutional council will take place on July 24

RUSSIA

* Despite the high prices for oil and other primary commodities, Russia should work to overcome its dependence on oil revenues, Prime Minister Vladimir Putin said

* Mikhail Simonov, the former chief designer at the Sukhoi aircraft design bureau who was known as the father of the Su-27 family of fighter jets, died aged 81

* Finnish prosecutors will not press charges against Paavo Salonen for bringing his son from Russia in an ongoing child custody dispute with the boy's Russian mother, Rimma Salonen, her lawyer said

BUSINESS

* RusAl, the world's largest aluminum producer and a core shareholder of Russia's Norilsk Nickel, has rejected Norilsk's offer to buy a 20% stake in the nickel giant for $12.8 billion, RusAl said