Men armed with machetes and other weapons arrived at the protest scene and immediately sent protesters and bystanders scampering for safety.
Femi, 58, got to the scene moments later with his son Omorinmade Anikulapo-Kuti.
In a tweet, Femi urged the protesters to continue.
“Got to Alausa a while ago but hijackers had left. Continue the fight!” he wrote.
In another tweet, he said the armed men were chased away.
“Sorry the THUGS had been chased away. Well done,” he wrote.
Femi told a fan who hailed him for showing up in Alausa that the protest was for the youths and that he only came around because armed men invaded the protest.
He wrote: “It’s the protest of the youths. Only cause thugs were sent. It’s a peaceful protest no room for intimidation.”
It was gathered that one person was injured in the attack.
Femi had on October 12 joined the protest in Ajuwon area of Ogun State and allegedly prevented the police from shooting at the protesters.
The protests, which began on a peaceful note, became heated after the police alleged that the protesters hurled stones at them.
Some protesters were also detained until the legendary singer waded into the brewing crisis.
Femi who went there with son Made tweeted that he was in Ajuwon to stop the police from shooting at protesters and make sure the protest went on successfully.
Eyewitnesses at the protests alleged that the police, in order to disperse protesters, collected their cars and shot tear gas canisters.
Youths are protesting against police brutality, extortion and harassment following the scrapping of the notorious Special Anti-Robbery Squad (SARS).