After concerns that people wearing the hijab could be harassed on the streets of Sydney, locals took to Twitter to offer to travel with them on public transport using hashtag #illridewithyou. The hashtag has become a means of expressing solidarity with Muslims who might experience abuse following the hostage taking by an alleged Islamist.

The hashtag, which was initially started by Twitter user @SirTessa quickly gained popularity, spreading beyond Sydney to become a global trend.

In less than 12 hours, the hashtag had been tweeted more than 160,000 times, according to Topsy.

In Germany, the hashtag comes ahead of right-wing protests by the anti-Islamization movement PEGIDA. And many Germans have taken to Twitter using #illridewithyou to show their solidarity with the Muslim community in the country. The hashtag was trending earlier in the day, along with #Pegida which has been among the most discussed topics on social media in recent weeks.