Zeid described "concordant reports of acts of appalling barbarity committed against the Rohingya, including deliberately burning people to death inside their homes, murders of children and adults; indiscriminate shooting of fleeing civilians; widespread rapes of women and girls, and the burning and destruction of houses, schools, markets and mosques".
The government of the Buddhist-majority country should not only carry out its plan to repatriate the Rohingya who have fled to Bangladesh, but it should also grant citizenship to the largely stateless and marginalized group.
Zeid slammed "widespread, systematic and shockingly brutal" attacks against the Rohingya, as well as policies that had dehumanised and segregated the minority, and left it wallowing in statelessness for decades.
In today's resolution, the UN Human Rights Council condemned the systematic and gross violations of human rights in Myanmar, in particular against the Rohingya in Rakhine State.
Bangladesh, which along with Saudi Arabia had requested the special session, meanwhile voiced disappointment that Tuesday's resolution was not adopted by consensus, given the severity of the crisis.
That from the UN's top human rights official at a special session of the Human Rights Council in Geneva.
Myanmar's ambassador Htin Lynn said his government "disassociated" itself from the text and denounced what he called "politicization and partiality".
"Given all of this, can anyone, can anyone rule out that elements of genocide may be present?" asked Zeid.
The resolution calls on Myanmar to "address the root causes" of the Rohingya crisis, and to fully cooperate with the different United Nations bodies, providing full access to investigators and humanitarian workers.
Al Hussein said his office has visited and interviewed Rohingya refugees in Bangladesh three times this year.
"We have not come to any conclusion on these issues but we are taking such allegations very seriously and are examining them in depth", he told the council in a recorded video message.
He spoke at a special council session on the Rohingya on Tuesday.
Rights advocates hailed the resolution. "The Myanmar authorities continue to downplay the seriousness of the reports, while refusing to cooperate with the fact-finding mission created by this Council".
"How much do people have to endure before their suffering is acknowledged and their identity and rights are recognized, by their government and by the world?"
"The U.N. resolution makes clear that the worldwide community retains a watchful eye over the plight of the Rohingya and demands action", said Laila Matar, senior U.N. advocate at Human Rights Watch, in a printed statement.
Zeid said he had reported to both the Human Rights Council and the Security Council about the persistent allegations of serious human rights violations by security forces.
"Those responsible for atrocities should be identified, sanctioned, and held to account", Matar said. A draft resolution urges Zeid's office to report on cooperation between Myanmar's government with United Nations rights monitors.
Instead, it issued a presidential statement calling on the Myanmar government to end the use of excessive military force and intercommunal violence that has devastated Rohingya communities during the military crackdowns.