Media playback is unsupported on your device Media caption Fireworks in major cities have ushered in the New Year, from Sydney to New York

Fireworks have lit up the skies over some of the world's most iconic landmarks as people across the globe gather to welcome the new year.

From Sydney to Moscow, Paris to New York, crowds said goodbye to 2016, a tumultuous year in global politics.

Many cities stepped up security for New Year's Eve celebrations, after a year in which attackers drove lorries into crowds in Nice and Berlin.

Thousands of extra police have been on duty in London and other cities.

But it did not stop tens of thousands lining the River Thames to watch a fireworks display with one very clear message after the country voted to leave the European Union: "London is open."

Image copyright Getty Images Image caption London brings the new year with fireworks along the Thames

Image copyright Reuters Image caption Paris's Arc de Triomphe was lit up with pictures

Image copyright Reuters Image caption Fireworks explode over the Brandenburg gate in Berlin, Germany

Image copyright AP Image caption Fireworks explode over the Kremlin, in the Russian capital, Moscow

Image copyright AP Image caption As midnight struck in New York, Times Square was deluged with confetti

It also failed to dampen spirits in Paris, where about 500,000 people poured into the Champs-Elysees, where the Arc de Triomphe was lit up with a colourful countdown and the word "welcome" in dozens of languages.

Revellers in Berlin were undeterred by the recent terror attack at a Christmas market, gathering for a series of concerts before a midnight fireworks display.

Image copyright AP Image caption People watch a fireworks display from the water off Copacabana beach, Rio de Janeiro, Brazil

Image copyright Reuters Image caption Greece welcomes 2017 with a fireworks display over the Parthenon temple

Image copyright Getty Images Image caption Fireworks lit up the world's tallest building, the Burj Khalifa in Dubai

Image copyright AP Image caption Buddhists light candles at Jogye Buddhist temple in Seoul, South Korea

Some 2,000 police watched over the around two million people enjoying a fireworks display on Rio de Janeiro's Copacabana Beach which had been shortened this year due to a severe economic crisis.

But the 17,000 police officers on duty in the Turkish city of Istanbul were unable to prevent an attack on a nightclub less than two hours into 2017, which left at least 39 dead.

Pacific islands including Samoa, Tonga and Kiribati were the first to enter 2017 at 10:00 GMT, followed an hour later by Auckland, where fireworks erupted from the 328m (1,080ft) tall Sky Tower in the city centre.

Image copyright AP Image caption Singapore celebrates the new year

Image copyright EPA Image caption Fireworks ring in the New Year in Kuala Lumpur, Malaysia

The iconic midnight fireworks display at Sydney Harbour in Australia paid tribute to Prince and David Bowie, two music superstars who died in 2016.

Seven tonnes of fireworks were set off in two displays watched by about one and a half million people.

On Friday a man in Sydney was charged in connection with threats made against Sydney's New Year's Eve celebrations.

Image copyright Reuters Image caption People in Madrid celebrate the New Year

Image copyright AFP Image caption Celebrations in Baghdad, Iraq, took place under heavy security

Image copyright EPA Image caption Fireworks light up the sky over Nairobi, Kenya

Police said he was charged with a "crimes act offence, but not a terrorist offence" and there was no continuing threat to the community.

Israel has also warned its citizens travelling in India to avoid crowds, saying there is a risk of imminent "terrorist attacks".

'Many enemies'

Meanwhile, US President-elect Donald Trump tweeted new year greetings, including to his "many enemies".

Mr Trump will be sworn in as US president on 20 January.

Image copyright Twitter

A "leap second" was added to the countdown just before midnight in countries in the GMT timezone, such as the UK, to compensate for a slowdown in the Earth's rotation.

The extra second occurred just before clocks struck midnight and a time of 23:59:60 GMT was recorded, delaying 2017 momentarily.

This is required because standard time lags behind atomic clocks.

Image copyright AP Image caption North Koreans gathered at Kim Il Sung square in Pyongyang