Early Wednesday, London became the site of the latest terrorist attack when a car struck several pedestrians on Westminster Bridge and an attacker stabbed an unarmed officer. As the number of victims continues to grow—the BBC is reporting four fatalities, not including the attacker, and 40 wounded—the tragedy becomes more harrowing and pronounced. While the incident is still being investigated, there are ways to reach out, grieve, memorialize and give back to those in shock and mourning.

Here’s what you can do:

Use Facebook to Check on Friends in London

Facebook has enacted its safety check tool in the wake of the incident. If you’re in London, you can mark yourself as “safe” here. The feature also allows you to check on friends who might have been nearby at the time of the attack. Click on “check if safe” to notify friends and loved ones in London of your concern.

Be Thoughtful of What You Share

In times like these, a scroll through Twitter or Facebook can be toxic for those who are damaged from these events. It’s important to think of what information is useful, and what isn’t, which attitudes create positive change, and which just perpetuate harmful beliefs. When documentation of violent acts circulates, remember that while you may find it informative, others may find those images harmful. Be thoughtful of what you’re sharing, and remember that while social media posts may appear small, they can have a big emotional impact.

Donate to Helpful Resources

Even if you’re not in London, you can still make a difference. Aid workers and first responders always need support. Consider making a donation to emergency resource organizations like the Red Cross. (Here’s a link to the British Red Cross.)

Do you have other ideas for helping the victims of London’s attack? Please share with us @BritandCo.

(Photo by Carl Court/Getty Images)