The leader of Syria's most prominent opposition group has rejected Kofi Annan's call for dialogue with the government.
Burhan Ghalioun, president of the Syrian National Council (SNC), said on Friday that any solution to the crisis must be accompanied by military pressure on President Bashar al-Assad.
Annan, enlisted as an envoy by the Arab League and UN, said in Cairo on Thursday that "militarisation" of the conflict would only make it worse and said he aimed to reach a political settlement through dialogue.
The former UN chief, who is due to arrive in Damascus on Sunday, cautioned against military intervention, saying it had worsened other conflicts in the region.
"These kind of comments are disappointing and do not give a lot of hope for people in Syria being massacred every day," Ghalioun said.
"It feels like we are watching the same movie being repeated over and over again."
Ghalioun criticised Annan for "avoiding" any references to the essence of the problem, which he said was the government's use of extreme military force to crush year-long protests.
"As an international envoy, we hope he will have a mechanism for ending the violence," Ghalioun said. "My fear is that, like other international envoys before him, the aim is to waste a month or two of pointless mediation efforts."
The SNC, which has been trying to co-ordinate with opposition fighters inside the country, has called for international military intervention, though it is far from clear whether the majority of the opposition agrees.
Clashes erupted in the flashpoint Homs province on Friday morning, the DPA news agency reported.
"Heavy clashes were raging at the outskirts of the Rastan and al-Kussair areas between members of the [opposition] Free Syrian Army and government troops," Abu Imad, a Syrian activist based in northern Lebanon, said.
The Local Co-ordination Committees, an opposition group documenting violence across Syria, said troops were bombarding areas in Karam al-Zeitoun, al-Khalidiyeh and al-Bayada in Homs.
The army reportedly has sent reinforcements to the northwestern province of Idlib, where activists have been fearing an assault similar to the one that devastated the Baba Amr neighbourhood of Homs.
In his remarks on Thursday, Annan said the solution to the worsening conflict "lies in political settlement" and must be "Syrian-led and Syrian-owned".
"I hope no one is thinking seriously of using force in this situation," Annan said.
"As I move to Syria, we will do whatever we can to urge and press for a cessation of hostilities and end to the killing and violence."
Speaking to Al Jazeera from Washington DC, John McCain, the influential US politician, criticised those comments, saying they made him "wonder what planet Mr Kofi Annan is on".
McCain called for a coalition of Arab and Western states to intervene in Syria, similar to the group that organised to implement a UN no-fly zone in Libya.
The arms and support coming to Assad's government from Iran and Russia made the conflict with rebels an "unfair fight" and that Assad had shown no desire to make a deal, he said.
Clear Arab divisions
Al Jazeera's Rawya Rageh, reporting from Cairo, said clear divisions remained among Arab League countries, some of whom support armed intervention.
"Some have a hawkish stand, Saudi Arabia or perhaps even Qatar, when it comes to arming the Syrian opposition," she said.
"If you arm the opposition ... you exacerbate the possibility of an all-out civil war and the biggest risk, of turning Syria into a proxy battlefield for wars in the region."
In-depth coverage of escalating violence across Syria
The UN estimates that at least 7,500 people have died since protests first broke out a year ago.
Valerie Amos, the UN humanitarian chief, said she was "struck" by the devastation she saw during a visit to the shattered city of Homs on Wednesday.
Amos was allowed access to the former opposition stronghold of Baba Amr after the Free Syrian Army, a rebel group, withdrew in the face of a nearly month-long artillery barrage and a major government ground assault.
She said at a press conference in Ankara on Friday that she had made a request to the Syrian government for unhindered access to the worst-hit areas, but that the Syrian government had asked for more time.
The Syrian government had agreed to join UN agencies in a "limited assessment" of the situation, she said.
Amos said in Damascus on Thursday that Baba Amr is "completely destroyed" and that most of its residents were gone.
She was the first independent observer allowed into the neighbourhood since government forces entered on March 1.
The army prevented aid convoys associated with the International Committee of the Red Cross from entering for more than three days.
"The devastation there is significant, that part of Homs is completely destroyed and I am concerned to know what has happened to the people who live in that part of the city," Amos said.
UNESCO resolution watered-down
The UN's cultural agency, the Education, Scientific and Cultural Organisation (UNESCO), condemned Syria on Thursday for its crackdown on a year-long uprising but did not expel Damascus from its human rights committee as some Western and Arab countries had demanded.
Angered by Syria's inclusion on the committee, a group of Western and Arab nations had pressed for Syria's expulsion
following the violence in the country.
But a resolution, submitted by Saudi Arabia, Tunisia, Britain, Denmark, and other countries, stopped short of expelling Damascus from the key committee.
Ziad Aldress, Saudi Arabia's ambassador to the UNESCO, told Al Jazeera that it was impossible to use stronger language without losing crucial support for the resolution.
"If we lose the votes then it will be a hopeless case," he said.
Al Jazeera's Jacky Rowland reported that some UNESCO officials were unhappy about the way their organisation was being used as a forum for international disputes.
"Some officials at UNESCO told us privately that they are getting quite tired of playing the role of a political football," she said.
"What we've seen here today, once again, is the limitations of international diplomacy when it comes to trying to move forward in consensus on the subject of Syria," she said.