Feature: London landmarks illuminated in French colors to show solidarity

London's major landmarks were illuminated in colors of the French national flag on Sunday to show solidarity with Paris where a series of deadly armed attacks killed 17 people in the past week.

Trafalgar Square, the National Gallery and Tower Bridge were all lit in blue, white and red to pay respect to the victims of the fatal attacks at the office of French satirical magazine Charlie Hebdo and two subsequent sieges in Paris.

Thousands of people, with many holding placards, pencils, French flags and portraits of the victims, gathered at Trafalgar Square for a unity rally at the same time when a massive march took place in Paris on Sunday afternoon.

"Thanks to all at London's gathering of solidarity with Paris - cities of freedom united in the fight for that freedom," said London mayor Boris Johnson, who was present at the rally.

He tweeted that the lighting was just "one example of London's incredible response to events in Paris."

British Deputy Prime Minister Nick Clegg and the French Ambassador to Britain Sylvie Bermann also joined the crowds at Trafalgar Square, where a vigil was held in tribute to the victims.

Prime Minster David Cameron and the Labor Party leader Ed Miliband both traveled to Paris on Sunday to join other world leaders in an unprecedented march against extremism, which reportedly saw more than 1 million people taking part.

German Chancellor Angela Merkel, Italian Prime Minister Matteo Renzi, Spanish Prime Minister Mariano Rajoy, European Commission President Jean-Claude Juncker, European Parliament President Martin Schulz and European Council President Donald Tusk were among the foreign leaders present at the march.

"People wanted to show real solidarity with the victims, and that's why it was right to come to show solidarity with the French people after these appalling attacks, but also to recognize we face the same threat," Cameron said after the rally.

"We have to confront it in our own country -- keeping our security strong, but also taking on this poisonous narrative that is radicalizing young minds wherever we find it. And that work continues," the prime minister added. Endit