The anti-Buhari group said it was attacked by supporters of the absent president.
The protesters agitating for the return of President Buhari were attacked by hoodlums when they attempted to stage a protest at the popular Wuse market on Tuesday, August 15, 2017.
They were stoned and gunshot sounds were reported as police officers took over the market and restored calm.
Adeyanju released a statement after the incident to point the finger of blame at "known supporters of President Muhammadu Buhari".
He stressed that the group will refuse to be intimidated and carry on with the protests that started on Monday, August 7.
His full statement read, "This morning, members of our movement -#ResumeOrResign - were attacked by known supporters of President Muhammadu Buhari while on a visit to Wuse Market.
"The attack was spearheaded by a member of the pro-Buhari support group that meets at the Unity Fountain. This attack was completely unprovoked.
"This is the third in a series of attack carried out against us using a combination of policemen and paid hoodlums.
"It is saddening that the administration of President Muhammadu Buhari would rather commit scarce national resources to such underhand tactics than give full disclosure regarding the health of the President.
"We reiterate commitment to remain resolute in demanding full disclosure regarding the state of health of the President.
"It is the right of the Nigerian people to know the true state of health of the man they voted into power and for whose health care they are paying.
"We also restate our commitment to remain law abiding in the face of such constant provocation. Our right to freedom of speech and peaceful assembly are constitutional rights that we will not allow to be abrogated."
Leader of the 'Our Mumu Don Do' movement, Charles Oputa, also known as Charlie Boy, was almost lynched by the group of hoodlums and had his car destroyed in the process.
The group has been staging a sit-out protest at the Unity Fountain since Monday August 7, demanding that the president should either return to the country he left over three months ago, or resign from his position.
On Tuesday, August 8, the group was attacked by the police at Unity Fountain with tear gas cannisters and water cannons, in a move that was roundly criticised by the Nigerian public.
On Thursday, August 10, pro-Buhari groups, like the Coalition for Good Governance and Change Initiative, marched the streets of Abuja in support of the president who has been out of the country for 100 days.
On Friday, August 11, both groups met at Unity Fountain, and trouble almost broke out before it was promptly contained by the police.
President Buhari left the country on May 7 to resume treatment for an undisclosed illness in London, leaving Acting President Yemi Osinbajo in charge of the country's affairs.
The president has said he is completely healthy and is only waiting for a clean bill of health from his doctors before he returns to the country, but there has been no confirmed date for his return.