* Syria says Brahimi abandon neutrality in U.N. remarks
* Brahimi criticised Damascus over response to talks offer
* Envoy says situation appears "totally hopeless"
Syria accused international envoy Lakhdar Brahimi on Wednesday of bias and interference after he criticised its response to an opposition offer of talks and suggested Bashar al-Assad should not stand again for president.
Brahimi told a closed-door session of the United Nations Security Council last Friday that Damascus was "surprised and embarrassed" by a January offer of talks from opposition leader Moaz Alkhatib, and its response was "slow and confused".
At the conclusion of his remarks, which were later circulated by U.N. diplomats, Brahimi suggested Assad "voluntarily forego" the right to stand for another term as president in an election scheduled for next year.
Syria's foreign ministry said in a statement that if Brahimi wished to continue his role, he must show impartiality and realise that "the Syrian people are the only decision-makers who will choose their representatives".
"The briefing ... was marked by interference in the Syrian Arab Republic's internal affairs and a lack of neutrality which should characterise his mission," the ministry in a statement.
The ministry also said it would treat the veteran Algerian diplomat, who is the joint United Nations and Arab League envoy for Syria, as a purely U.N. envoy because it considered the Arab bloc as "a party to the conspiracy" against Assad.
Wealthy Gulf Arab states like Qatar and Saudi Arabia, which hold sway over the League, have thrown their weight behind the rebels fighting to topple four decades of Assad family rule.
Brahimi offered a bleak verdict on the conflict in which 70,000 people have been killed, according to the United Nations, and at least five million people have been displaced including 1.2 million refugees in neighbouring countries.
"The regime is not quite ready to listen (to peace proposals)," he said, and "the opposition is not as united as it should be around an established leadership and a credible, constructive political programme," he said.
"Yes, this situation appears to be totally hopeless, with no light to be seen at the end of a long tunnel Syria is lost in."
"Almost 50 percent of the Syrian population are being gravely affected by the conflict. I wonder if this is not a depressing record in the history of conflict," he said.
Brahimi, appointed last year after the resignation of Kofi Annan, has made no secret of his frustration at the lack of progress towards a political solution to Syria's civil war, chiding world powers whose political deadlock has paralysed the Security Council.
In his briefing, he also criticised the Arab League for endorsing an opposition interim government, a move he said undermined any prospect of dialogue, and also criticised the opposition itself.
Just weeks after Alkhatib's personal offer of talks with representatives of Assad's government - which Brahimi described as "a ray of hope in a profoundly bleak situation" - he said the opposition's elected interim prime minister Ghassan Hitto had killed off those hopes by ruling out dialogue with Damascus.
"On his part, President Bashar al-Assad in his long television interview (last week) again spoke of the opposition and of his understanding of dialogue in terms that are hardly encouraging," Brahimi said.
Assad said in the interview the government was ready for talks, but they must be with what he described as a "national opposition", not groups which he said were foreign backed and serving the interests of Syria's foe Israel.
Brahimi's frustration came out in public on Friday when, pressed over reports that he planned to step down, he said he had not resigned, but added: "Every day I wake up and think I should resign. One day perhaps I will."