Malaysia's iconic Petronas Twin Towers joined other famous landmarks around the world in marking the 70th anniversary of the United Nations by being lit up in blue.

The occasion was highlighted by Prime Minister Datuk Seri Najib Tun Razak on his Facebook page with an accompanying picture of the majestic towers shimmering in blue in downtown Kuala Lumpur.

"Today, we illuminate our Petronas Twin Towers to join the celebration of 70 years of United Nations. Spectacular sight," he said.

Apart from the Kuala Lumpur landmark, other structures taking part in the event included the Sydney Opera House, Paris' Eiffel Tower and the Empire State Building in New York.

Oct 24 is the anniversary of the entry into force of the UN Charter in 1945 and is celebrated as UN Day.