Four mosques in the city had windows smashed with a sledgehammer during the early hours of Thursday morning, West Midlands Police said.
Damage to a mosque in Birchfield Road was first reported to officers at around 2.30am, before a further attack in Slade Road, Erdington, took place at 3.15am.
Police patrols around areas with mosques were then set up, during which damage was also discovered in Witton Road, Aston, and Broadway, Perry Barr.
Officers said the incidents were being treated as linked and although they appeared to be targeting the Muslim community, no exact motive had been determined.
The investigation comes at a time of heightened concern for the safety of Muslims in Western countries, following a terror attack in Christchurch, New Zealand, where 50 people died after a gunman opened fire at two mosques last Friday.
Counter terror police in the UK have stepped up monitoring activity at places of worship and other areas deemed at risk following the shootings.
Javid Iqbal, a spokesman for Witton Islamic Centre, one of the places of worship targeted, said the incidents were worrying given the New Zealand attack.
“We’ve had a white intruder strike in the middle of the night. He has arrived with a sledgehammer and smashed one window.
“The force of the swing has actually meant he had lost his grip and the sledgehammer ended up in the middle of the mosque.”
Mr Iqbal claimed the attacker returned half an hour later with another hammer, which he used to cause more damage.
“Whatever the case, it is just a minority of idiots that do not reflect the values of this city or this community, he said.
“Following the New Zealand terror attacks, we have seen people in that country from all faiths come together in solidarity.
“Many non-Muslims, whether they be Christians, Hindus, Jews or whatever religion have pulled together to support one another.”
Neighbourhood officers from are expected to be deployed to work closely with mosques across the West Midlands on Thursday.
West Midlands Police forensics experts are working to identify evidence at the scenes of the four attacks, while CCTV is also being examined.
“Since the tragic events in Christchurch, officers and staff from West Midlands Police have been working closely with our faith partners across the region to offer reassurance and support at mosques, churches and places of prayer,” the force’s chief constable, Dave Thompson, said.
“At the moment we don’t know the motive for last night’s attacks. What I can say is that the force and the Counter Terrorism Unit are working side-by-side to find whoever is responsible.
“At difficult times like this, it is incredibly important that everyone unites against those who seek to create discord, uncertainty and fear in our communities.”
Additional reporting by SWNS