SSS arrested Mr Ajaero at the airport in Abuja on Monday while trying to catch a flight to the United Kingdom to attend an event of the World Trade Union Congress (WTUC).
The State Security Service (SSS) has released the president of the Nigerian Labour Congress (NLC), Joe Ajaero, after detaining him for about 15 hours on Monday.
The SSS released him at about 11 p.m. on Monday but seized his passport.
He was released to his lawyer, Abubakar Marshall, from Falana and Falana Chambers after 15 hours of detention since his arrest at about 7 a.m. on Monday at the Nnamdi Azikiwe International Airport, Abuja.
Confirming Mr Ajaero's release, Mr Abubakar told PREMIUM TIMES Monday night that the labour leader was released to him as his lawyer. He said the secret police tasked him with presenting him for further interrogation whenever the need arose.
"The NLC President, Joel Ajaero, has returned to his home," he said.
PREMIUM TIMES reported that Mr Ajaero was arrested at the airport in Abuja on Monday while trying to catch a flight to the United Kingdom to attend an event of the World Trade Union Congress (WTUC).
Mr Ajaero's detention sparked widespread criticism of President Bola Tinubu's administration, including from Amnesty International, which demanded an unconditional release of the labour leader on Monday.
The NLC, in a statement by its spokesperson, Benson Upah, also said Mr Ajaero's "arbitrary arrest" depicted "an escalating crackdown on human rights and restrictions on civic space by the government of President Bola Tinubu."
Another of Mr Ajaero's lawyers, Maxwell Opara, condemned the arrest in an interview with PREMIUM TIMES on Monday.
He said the labour leader had informed the SSS about his trip to the United Kingdom for an official engagement.
The lawyer said the SSS had invited Mr Ajaero a couple of days ago via telephone call but that he told the secret police that he would honour the invitation on Monday, September 16, upon his return from the UK to Nigeria.
"They (SSS) invited him on the phone. He told them that he was engaged with the World Trade Union Congress. He had committed to meeting with the SSS on Monday when he returned from the UK," Mr Opara told PREMIUM TIMES in a telephone interview on Monday.
Mr Opara accused the Nigerian government of attempting to undermine Mr Ajaero's advocacy and leadership of the NLC by arresting him.
According to the lawyer, the arrest is part of a broader strategy to disrupt the NLC president's efforts on behalf of Nigerian workers.
Mr Opara accused the government of plotting to remove the labour leader from office and replace him with somebody more aligned with its interests.
"The government wants to push him out," Mr Opara said. "The SSS claimed Mr Ajaero was invited, despite his clear communication about his availability. This is a deliberate attempt to disrupt his work.
"The timing and nature of this arrest suggest an effort to weaken Mr Ajaero's influence and consolidate control over the labour movement," he added.
The NLC and Mr Ajaero have been having a running battle with the Nigerian government.
The police have invited him on two occasions, one of which involved the 70-year-old British socialist Andrew Wynee, who runs a bookstore in the Labour House building, where the NLC headquarters is located.
Citing Mr Wynnee's connection with the organisers of the #EndBadGovernance protests held across many states in August, the Nigerian government declared him wanted last week over an alleged attempt to topple President Bola Tinubu's government.
Mr Wynne has dismissed the allegation, maintaining that protests are not treason as alleged by the government.