Graffiti is not often associated with positive messages, but the "vandalism" left at a US mosque from a particular group of "hooligans" was unusually heart-warming.

"You are loved," "we are your brothers & sisters" and "we are with you" were some of the messages of acceptance drawn onto paths leading into the Mubarak Mosque in Chantilly, Virginia.

One of the chalk messages left as a sign of support to members of the mosque. ( Supplied: Muslim Youth CVA )

The anonymous supporters used chalk to fight back against anti-Muslim sentiment that has seen a surge in the United States, especially after President-elect Donald Trump while campaigning called for a ban on Muslims.

The gesture meant even more in light of the fact that when the Mubarak Mosque was being built in 2012 it was subject to major vandalism, with about $US60,000 ($81,000) worth of damage caused.

A member of the mosque, Qasim Rashid, posted photos of the artwork on social media saying "some sneaky hooligans 'vandalised' my mosque over the weekend" and described them as Muslim allies.

Hibbi Iqbal, who also attends the mosque and is the secretary of public affairs in the Ahmadiyya Muslim community, was part of a group that arrived at the mosque early on Monday and saw the chalking.

"We couldn't help but be awe-struck," he told the ABC.

"The kids were beaming with delight and everyone else began pulling out their cameras in a race to be the first to spread the word to other members.

"The mystery 'vandals' even left flowers by the door as if they didn't do enough already."

Mr Iqbal says no-one has "the faintest of ideas" as to who came and left the messages, but said the mosque has a strong relationship with its neighbours who they often invite to events.

"It wouldn't surprise us at all if it was a group from any of the other religious communities in the area either," he said.

This is the mosque's first taste of community feedback post-US election and "boy was it a good one", Mr Iqbal said.

The mosque has invited those who left the drawings to return so the mosque's members can "reciprocate the love".

"If we are just with our friend and neighbours, they will be just with us and at the end of the day these are the bonds that will unite us against any forces seeking to destroy," Mr Iqbal said.