Within hours of Brussels attacks Tuesday tens of thousands of people were sharing images on social media of the country's most famous creation in tears.

With many invoking Herge's cub reporter -- who always got the better of the baddies in the end -- one Twitter user put words into the boy hero's mouth: ‘Let's be strong, together and humane faced with these crazies.

‘We are all Belgians,’ said a user called Ulysse, who lives in Paris.

French film-maker and graphic novelist Joann Sfar had Tintin consoling his sidekick Captain Haddock: ‘Sometimes I want to leave for the Moon, Captain.’

But the most shared image of all was one showing a figure dressed in French colours putting an arm around a crying Belgian flag.

The drawing by the acclaimed cartoonist Plantu of France's Le Monde daily was captioned with the dates March 22 and November 13, the day 130 people died at the hands of jihadist gunmen and bombers in Paris.

As speculation turned to whether the same Islamic State cell had planned the attacks on both cities, several other widely-shared cartoons took a more defiant and typically irreverent Belgian tone.

One showed a packet of fries, the country's most famous street food, with one of them seemingly giving the terrorists the finger.

The Belgian cartoonist Marec continued the theme, with the Statue of Liberty holding a packet of fries as Brussels' landmark ‘Peeing Boy’ statue relieves himself onto the head of an Islamist extremist.

‘There are still 11 million of us,’ a Brussels lawyer tweeted soon after the attacks. ‘You are an annoyance but we won't give you the pleasure. Vive la frite!’ (Long live the fry!)

The Twitter hashtags #Belgium and #PrayForBelgium were trending across Europe and the United States as thousands offered their sympathy and support, while in France another hashtag appealing for Muslims not to be blamed made the top three.

Hundreds of people also offered to shelter people stranded by the transport chaos after the attacks with the hashtags #openhouse in English, French and Flemish.

Facebook put its ‘Safety Check’ option into action so people in the area could let their friends and relatives knows they were safe, although some users criticised its slowness to do so.

But a more sour tone was struck by the pro-government Turkish newspaper, the Star. It labelled the country ‘Terrorist Belgium’ on its front page on the morning of the attacks for allowing pro-Kurdish protests to take place Brussels.