The international envoy seeking to end Syria's civil war has warned that the failure of the government and rebels to pursue a political solution could lead to the "full collapse of the Syrian state" and threaten world security.
Mr Brahimi has reported little progress in his mission to push forward a peace plan for Syria first presented in June at an international conference in Geneva. The proposal calls for an open-ended ceasefire and the formation of a transitional government to run the country until elections can be held and a new constitution drafted.
The regime of president Bashar Assad and the scores of rebels groups fighting his forces across the country have so far shown no interest in negotiations.
The rebels' political leadership has called Assad's departure a pre-requisite for any political solution, and it is unlikely that the opposition's National Coalition could even stop rebels on the ground from continuing to fight. Likewise, it is doubtful that senior members of Assad's regime will voluntarily give up power.
The Syrian government has not commented officially on Mr Brahimi's plan, which he has pushed in the past week in meetings with Assad in Damascus, leading Russian officials in Moscow, and on Sunday with the head of the Arab League in Egypt.
Mr Brahimi said: "Peace and security in the world will be threatened directly from Syria if there is no solution within the next few months. The alternatives are a political solution or the full collapse of the Syrian state."
Since meeting Assad early last week, he has given no indication how his plan was received. When asked on Sunday if there is any willingness among the opposition to enter a political process, Mr Brahimi said: "No, there isn't. This is the problem."
Syria's crisis began in March last year with political protests against Assad. The conflict has since evolved into a civil war. Anti-regime activists say more than 45,000 people have been killed.
The Syria government does not give death tolls for the conflict and says the rebels are terrorists backed by foreign powers who seek to destroy the country.