The men, deemed to be of fighting age by the Syrian authorities, were among 1151 who left the besieged rebel-held Old City of Homs during an agreed ceasefire that was extended for another three days until today.
The UN-brokered "humanitarian pause" has also allowed aid to get into the old quarter of Homs which has been surrounded by President Bashar al-Assad's forces for more than 18 months.
Homs governor Talal al Barazi said about 100 men had been questioned and released, but the UN has so far reported the release of only 41. The men have been questioned in a school, under the "general monitoring" of protection staff from the UN refugee agency UNHCR and the UN children's agency UNHCR.
A UN spokeswoman said: "These are interviews the UN is not necessarily privy to. These are security screening interviews."
Aid and evacuations operations were halted yesterday afternoon for logistical reasons, Mr al Barazi said, but are due to resume today.
The ceasefire deal originally stipulated only women, children and men over 55 years of age would get safe passage. But on Sunday, Mr Barazi said anyone could leave, though men aged between 15 and 55 would be questioned and put through a "judicial process", which could include an amnesty.
Opposition activists have raised fears some Homs evacuees, particularly men, could encounter dangers such as those faced by residents who fled the besieged rebel-held town of Mouadamiya, near the capital Damascus, in October. Security forces detained dozens of men, many of whom have not been freed.
The UN human rights office said any evacuee, including those who had laid down their arms, must be protected from acts prohibited under international law, including torture and humiliating and degrading treatment.
Its spokesman added: "We are deeply concerned to learn a number of boys and men and their families were seized by the authorities as they left the besieged area. It is essential they do not come to any harm."
The Old Homs ceasefire has been the first tangible result of the Geneva 2 peace talks which began their second round yesterday.
International mediator Lakhdar Brahimi said not much progress was being made. He added: "The beginning of this week is as laborious as it was in the first week."
The UN says it does not know how many people are still in Old Homs but some estimates suggest the area has about 2500 residents - a small percentage of the more than quarter of a million the UN estimates are trapped in rebel-held areas across Syria.
Meanwhile, Syria's ambassador to Russia said the most dangerous elements of President Assad's chemical weapons stockpile would be removed from the country by March 1 after Syria had missed an earlier deadline.