* Mediator says talks "laborious"
* Rival sides have nothing new to report
* Syrians questioning men allowed to leave Homs
Peace talks between the Syrian government and opposition are not making much progress, international mediator Lakhdar Brahimi said on Tuesday after a face-to-face meeting of the warring parties in Geneva.
As negotiations intended to end Syria's three-year-old war concluded the second day of this week's session, both sides had no advances to report.
Brahimi, a veteran diplomat charged with running the internationally sponsored talks, said he planned to report to U.N. Secretary General Ban Ki-moon and the Security Council within the next few weeks.
"The beginning of this week is as laborious as it was in the first week. We are not making much progress," he told a news conference at United Nations headquarters.
Syrian Deputy Foreign Minister Faisal Mekdad said Tuesday was a "lost day" while opposition spokesman Louay Safi said "no progress" had been made.
In an attempt to address the main questions confronting the rival delegations, Brahimi had proposed that they discuss ending the violence on Tuesday and the formation of a transitional governing body on Wednesday, delegates say.
But the two issues have caused deep rifts and delayed negotiations, which started last month with little result and resumed this week.
A main issue is the role of President Bashar al-Assad in a transitional governing body. The government says it will not discuss his leaving power while the opposition wants him out.
Mekdad said no agenda had been agreed for the talks, blaming the opposition's refusal to discuss the issue of "terrorism" which he says much be covered first. He said the government considers almost all those fighting it in Syria as "terrorists".
"Today was another lost day because the representatives of the (opposition) Coalition insisted that there is no terrorism in Syria," he said.
National Coalition spokesman Safi said: "It is obvious the regime is stalling and still believes in a military solution."
Specifically, he said the opposition and the government disagreed over the issues of violence and political transition, with the opposition seeing the creation of a transitional governing body as vital to the stability of the country.
Anas Abdah, a strategist in the opposition team, said "the regime is consistently trying to get rid of the transitional governing body. Today it basically refused to discuss it".
A statement from the Coalition said today's session was very tense and accused the government of attempting to "stall the talks".
There had been hopes for Tuesday's talks after they began with a minute of silence for the 130,000 people killed in Syria since the conflict began.
So far, the only tangible result of the talks process has been an agreement to allow aid into the Old City of Homs, where rebels have been under siege for more than year, and to allow people to leave.
United Nations officials said Syrian authorities were questioning men who had left Homs as part of the deal to evacuate people from the central Old City, raising concerns about their welfare. The U.N. said Syrian authorities had detained 336 men and were questioning most of them without direct supervision by a neutral third party.
The men, deemed to be of fighting age by the Syrian authorities, were among 1,151 who left the Old City during a ceasefire that was extended for a second three-day period on Monday.
Forty-one of the men have been released, but the rest are being questioned in a school, under the "general monitoring" of U.N. staff, Melissa Fleming, spokeswoman for the U.N. refugee agency UNHCR told a briefing in Geneva.
She said the United Nations was "concerned in general about how they're faring, what's their health situation, what are their concerns".
Rupert Colville, spokesman for the U.N. human rights office, said any evacuee must be protected from cruel treatment, torture and humiliating and degrading treatment.
"We are also deeply concerned to learn that a number of boys and men and their families were seized by the authorities as they left the besieged area. It is essential that they do not come to any harm," he said.
The evacuees included five women in the late stages of pregnancy, including one who was in labour and gave birth in hospital shortly afterwards, said World Health Organization spokeswoman Fadela Chaib.
Those leaving were very weak, with signs of malnutrition, said World Food Programme spokeswoman Elisabeth Byrs.
"They said that daily they survived on leaves, grass, olives, and sometimes some wheat flour appeared and they were mixing flour with water to make a kind of bread."
The United Nations says it does not know how many people are still in Old Homs - just one of the many sieges that have trapped more than a quarter of a million Syrians.