Some Australian social-media users are sending a message of solidarity to Muslims as the Sydney cafe siege stretches on, offering to accompany anyone who feels intimidated.

Hostages were still being held early Tuesday inside Sydney’s Lindt Chocolat Cafe by a gunman who had a flag bearing an Islamic declaration used by jihadis. That has prompted speculation it’s a lone wolf terrorist attack and raised fears of retaliatory attacks on Muslim Australians.

Sydney resident Rachael Jacobs wrote on Facebook she had seen a woman on the train remove her headscarf and offered to walk with her.

That spurred a Twitter campaign in which users offered to travel on public transit with those in Islamic dress who felt insecure. The hashtag #IllRideWithYou was used more than 90,000 times by late Monday.