A Twitter campaign called #IllRideWithYou spread across Australia today following news that a gunman, reportedly Muslim, had taken hostages in a Sydney cafe.

Amid the chaos, Australians banned together in hopes of combating “anti-Muslim sentiments” and started a Twitter campaign using #IllRideWithYou.

The hashtag began after an Australian woman named Rachael Jacobs saw a Muslim woman on the train removing her hijab, a veil worn by Muslim women that covers the head and chest. Jacobs told the woman to keep the veil on, and she told the woman she would walk with her.

Jacobs took to Facebook to post about the encounter, where it was shared widely.

The movement quickly spread as a way to encourage solidarity with the Muslim community and began trending on the social media site worldwide.

The hostage crisis, dubbed the “Sydney Siege,” lasted 16 hours. Police identified the gunman as Sheikh Man Haron Monis, an Iranian refugee and Islamist cleric who wrote hate-filled letters to family members of Australian service members killed in conflicts abroad.

Monis had instructed hostages to hold up a black flag with white Arabic text and demanded a phone call with Australian Prime Minister Tony Abbott. Two people died, and three were seriously wounded.

Here are some tweets mentioning #IllRideWithYou: