Meanwhile, the US has stepped up pressure on the Syrian regime by imposing sanctions on the country's main bank - the state-owned Commercial Bank of Syria - and mobile phone operator, Syriatel.
"We are taking aim at the financial infrastructure that is helping provide support to Assad and his regime's illicit activities," said Under Secretary for Terrorism and Financial Intelligence David Cohen.
The move came amid increasing international pressure over the escalating crackdown, which has reportedly killed more than 1,700 people since the uprising began in March. Tens of thousands of people have reportedly been arrested.
Turkish Prime Minister Recep Tayyip Erdogan on Wednesday urged Syria's government to end its operations against civilian demonstrators, saying he hoped Damascus would take steps towards reform within the next two weeks.
"In Syria, the state is pointing guns at its own people," said Mr Erdogan. "Turkey's message to Assad is very clear: Stop all kinds of violence and bloodshed."
AnalysisPresident Bashar al-Assad shows no sign of backing away from his determination to confront the protests in his country head-on. While there is lots of talk of reform the reality is that since the UN Security Council statement of concern about what was going on there a week ago, the crackdown against demonstrators has actually intensified.
The Security Council is due to meet again on Wednesday to discuss Syria. But the UN has relatively few tools in its armoury. Even though Russia has become more critical of President Assad's handling of the crisis it is far from clear that there would be consensus on tough economic sanctions.
The basic problem is that the Syrian regime is fighting for its survival. Up to now for all the talk in Western capitals about President Assad's waning legitimacy, nobody has gone so far as to openly back regime change.
And as the Libyan example shows, wishing regime change is one thing, delivering it quite another.
Envoys from India, South Africa and Brazil are expected to hold talks with Syrian Foreign Minister Walid al-Moallem later.
On Wednesday the London-based Syrian Observatory for Human Rights said one woman was killed and 13 people wounded when tanks and armoured vehicles entered Taftanaz and Sermin, outside the city of Idlib, about 30km (19 miles) from the Turkish border.
A member of the Local Co-Ordination Committees, an activist group that organises and documents the protests, says nearby Binnish was also attacked, and put the number of dead at five.
On Tuesday at least three people in Binnish were among dozens reported to have been killed around the country.
Asked why Binnish had been attacked, a resident told Reuters news agency: "The whole town has been joining in night rallies after Ramadan prayers."
Meanwhile, the restive central city of Hama has fallen quiet after an operation by the Syrian army that lasted more than a week and led to the deaths of dozens of opposition activists.
There are numerous police checkpoints but no visible army presence inside the city, says a BBC correspondent who visited Hama at the invitation of the Syrian authorities.
He saw the remains of barricades set up by opposition activists scattered by the roadside, as well as dozens of armoured personnel carriers and tanks being carried away from the city on trucks, which an officer said were being returned to their barracks.
In recent days large-scale operations by the Syrian army - notably in Hama and Deir al-Zour in the east - have drawn international condemnation.
Egyptian Foreign Minister Mohammed Amr is the latest Arab official to call for an "immediate end" to violence against civilians. Since Saturday, Saudi Arabia, Bahrain and Kuwait have recalled their ambassadors.
But efforts to persuade Syria's government to halt the crackdown have had little effect in the past week, during which more than 300 civilians are believed to have been killed.
The UN Security Council is due to resume debate on Syria later on Wednesday.
In its first statement on the crackdown last week, the Council condemned the violence and called for those responsible to be held "accountable".
The United States has been pressing for tougher international sanctions against Damascus. In May, President Barack Obama signed an executive order imposing targeted sanctions on Mr Assad and a number of high-ranking government officials.
There has been speculation that Mr Obama may call on Mr Assad to stand down.
Access to Syria has been severely restricted for international journalists, and it is rarely possible to verify accounts by witnesses and activists.