At least a dozen activists were arrested outside Parliament Buildings and Nairobi CBD as they gathered to mark the second anniversary of the June 25 Gen Z protests.
The police said they were questioning the group about their activities.
Nairobi police boss Issa Mohamud said they had detained the group at various police stations.
“I don’t know how many there are, but we have some people in custody for questioning,” he said.
He told those planning protests to keep off even as he defended the move to block major roads to the city centre.
“We were sieving thieves and crooks who were planning to cause chaos in the city. We did this for the sake of our country,” he said.
He told the protesters to be mindful of others’ rights. “Now that they have laid their flowers, they need to allow others to go on with their business,” he said.
The police had confronted a handful of protesters near the Nairobi Archives and arrested about seven people.
Others were arrested near Parliament after a group of protesters had laid their wreath outside a barricaded road to remember those who died in the past protests.
Along Thika Road at Githurai 45, people lobbed tar gas canisters to disperse a group of demonstrators.
The group was protesting the move by police to block them from driving to the city centre.
Police in plain clothes and uniforms dispersed the group and restored normalcy on the busy road.
Police had blocked major roads heading to the city centre as part of efforts to tame the planned protests.
Police commanders led by Inspector General of police Douglas Kanja, Deputy Inspector General of Administration Police Gilbert Masengeli and his Kenya police counterpart Eliud Lagat were on the streets patrolling.
Kanja visited the Kitengela area in the afternoon while the other commanders were in Nairobi.
Kitengela has, for the past few times, been a hot spot of protests. On Thursday, things were different as no protesters were seen.
More police officers were deployed in the area. Kanja said their strategies had borne fruit.
He said there were no cases of violence. “This is our country, and we need to be careful with some of these issues. So far, things are okay,” he said.
Meanwhile, the Kenya Human Rights Commission (KHRC) said police had defied a High Court order by erecting roadblocks along major roads leading into Nairobi’s central business district during commemorative protests held on Thursday.
In a statement, the rights group said the barriers had effectively locked thousands of people out of the city centre, disrupting movement and limiting access to essential services.
KHRC said the police action violated a court ruling obtained last year by Katiba Institute, which barred security agencies from obstructing public roads without issuing timely advance notice to enable members of the public to seek alternative routes.
"Authorities must dismantle the roadblocks and restore unimpeded passage for all,” the commission said.
The rights watchdog maintained that the extensive closures infringed on constitutional freedoms, including the right to movement, peaceful assembly and access to public services.
According to KHRC, the restrictions also affected access to healthcare facilities, emergency services and economic activities, placing what it described as an unlawful and disproportionate burden on millions of Kenyans.
The roadblocks were erected as Kenyans marked the anniversary of anti-government demonstrations that left dozens of protesters dead and hundreds injured in confrontations with security officers.
The commission said police used the barriers to frustrate citizens seeking to commemorate those who lost their lives during the protests.
“Police, open the roads now and let people commemorate the lives lost through your violence,” the statement read.
By Thursday morning, several roads leading to Nairobi’s central business district had been sealed off, with security officers conducting checks and restricting access to motorists and pedestrians.
