Activists reported that at least 23 people were killed across the country on Thursday [Reuters]

The United Nations says the death toll in Syria’s nine-month-old uprising has reached "much more" than 4000, characterising the situation as a civil war.

Navi Pillay, the UN High Commissioner for Human Rights, gave the latest figure on Thursday, a day before the global body is due to hold an emergency meeting on the crisis in the country.

"We are placing the figure at 4,000. But the information coming to us is that it's much more," she said during a conference in Geneva.

"I have said that as soon as there were more and more defectors threatening to take up arms, I said this in August before the Security Council, there was going to be a civil war.

"At the moment that's how I am characterising this."

Later in the day, Rupert Colville, Pillay's spokesperson, said Syria is on the cusp of civil war, clarifying the human rights chief's earlier remarks.

"It is definitely heading that way, with more and more reports of armed resistance to the government forces. It is on the cusp, but in these circumstances it is hard to say definitively at what point it becomes civil war."

In its report on Monday, the UN Independent Commission of Inquiry said Syrian forces had committed crimes against humanity, including the murder and torture of children, following orders from the highest levels of President Bashar al-Assad's government.

A previous toll issued by the UN earlier this month put the number of estimated deaths at 3,500.

On Thursday, the Local Co-ordination Committees activist network reported that at least 23 people were killed across the country, including two children. Most of the dead were in the central province of Hama.

Tightened sanctions

In a separate development, the European Union tightened sanctions against Syria's energy and financial sectors in response to Assad's crackdown on dissidents.

"The EU reiterates its condemnation in the stronget terms of the brutal crackdown by the Syrian government which risks taking Syria down a very dangerous path of violence, sectarian clashes and militarisation," the foreign ministers said in a statement after talks in Brussels.

The sanctions target "the energy, financial, banking and trade sectors and include the listing of additional individuals and entities that are involved in the violence or directly supporting the regime".

Diplomats said the measures include bans on exporting gas and oil industry equipment to Syria, trading Syrian government bonds and selling software that could be used to monitor Internet and telephone communications.

They also added that 12 more individuals and 11 more entities to a blacklist of people and companies hit by assets freezes and travel bans over the government's crackdown on protesters.

In response, Syria suspended its participation in the Mediterranean Union, Syrian state media said.

"Syria is suspending its membership in the Mediterranean Union in response to European measures taken against it," a statement carried by the official SANA news agency said.

The Mediterranean Union, an initiative of French President Nicolas Sarkozy, was inaugurated in 2008 to bolster cooperation between Europe, the Middle East and North Africa.

Also on Thursday, the US Treasury Department blacklisted Muhammad Makhluf, an uncle Assad, and Aus Aslan who was described as a general in the Syrian military and said Americans are banned from any dealings with them.

It also named the Military Housing Establishment as a Syrian government-controlled company that provides financing to the regime and Real Estate Bank, which the US department said handles borrowings by the government.

'Against intervention'

Meanwhile, the Arab League chief Nabil al-Arabi has rejected on Thursday any foreign intervention in Syria as he joined European Union talks aimed at ramping up pressure on Damascus.

"We reject any accusation that the Arab League is inviting any intervention," Arabi said.

"Every decision taken by the Arab League rejects an intervention," he added, days after the pan-Arabic body imposed its own unprecedented sanctions against Assad's government.

Syrian Foreign Minister Walid Muallem had accused this week "some League members" of "pushing to internationalise the conflict".

Separately, a member of the Syrian National Council (SNC), the country's main political oppostion bloc, said that the council and Syrian army deserters have agreed to co-ordinate their struggle against Assad's rule.

The first meeting between the SNC and the Free Syrian Army earlier this week in Turkey appeared to mark a change of tack from the SNC's previous reluctance to back the armed struggle.

"It is agreed that it would be a coordinated movement, there would be coordination," the SNC's Khaled Khoja told AFP news agency.

"The council recognised the Free Syrian Army as a reality, while the army recognised the council as the political representative" of the opposition."

He did not specify how organic the links between the two movements would be but the meeting marked a new step in efforts to unite opposition to Assad.