"The coalition did not conduct airstrikes near Camp Taji in recent days," Xinhua news agency reported citing the coalition as saying.
The Iraqi Joint Operations Command (JOC) also denied the media reports of the attack.
"What was reported by some media about an airstrike targeting a medical convoy of the Hashd Shaabi in Taji area is not true," said a statement by the media office affiliated with the JOC.
In the early hours of Saturday, media reports said that the medical convoy of the Hashd Shaabi forces was hit by the airstrike near a stadium in Taji, some 15 km north of Baghdad.
The Hashd Shaabi later issued a statement saying none of its leaders were killed in the attack.
However, an Iraqi Interior Ministry source told Xinhua that an attack against the Hashd Shaabi convoy did take place before dawn in Taji, leaving two killed and four others wounded, but the perpetrator of the attack was unknown.
This incident comes about 24 hours after a US drone attack ordered by President Donald Trump killed Qasem Soleimani, commander of the Quds Force of Iran's Islamic Revolutionary Guard Corps, and Iraqi militia commander Abu Mahdi al-Muhandis, who was the deputy chief of the pro-Hashd Shaabi forces.
The attack took place on the Baghdad International Airport road.
Iran's top leader Ayatollah Ali Khamenei and President Hassan Rouhani have vowed to retaliate against the US over Soleimani's death.
Friday's attack came after Iraqi protesters on Tuesday stormed the US embassy compound in Baghdad to protest the American air raids conducted on December 29 against five bases of Iran-backed militias in Iraq and Syria, claiming the lives of 25 people.
( With inputs from IANS )