Water was thrown over two women standing outside a mosque in an apparent fake acid attack, police are treating as racially aggravated assault.
The women, who were wearing traditional head coverings, were attacked as they waited outside the Bashir Ahmed Masjid in Southampton on Tuesday.
CCTV footage shows a black car slowing down next to them before speeding away. The pair react in horror before realising they are unhurt.
The mosque, in the southern city's Portswood district, has been forced to issue a safety warning to worshippers.
Police described the women as "understandably shaken" while on Facebook the mosque shared their fears that a subsequent attack could involve acid.
It follows a string of acid attacks, including five committed inside 90 minutes in London.
Footage suggests the assault took place at about 2pm local time.
A territorial police force's spokeswoman said: "We received a report yesterday regarding a racially aggravated assault in Portswood Road, Southampton.
"A woman reported that she was stood outside a mosque in Portswood Road, with her friend, when they had water thrown over them by someone in a passing car.
"Our investigations are continuing today and we are in contact with the victims who were understandably shaken by this incident.
"The vehicle is described as a black estate car."
Recent acid attacks have led to calls for tougher controls on corrosive substances, while British Home Secretary Amber Rudd has suggested acid attack convictions could soon carry life sentences.