Syrian TV has broadcast footage showing President Bashar al-Assad meeting Iran’s security chief, the first time Mr Assad has been seen on state television for more than two weeks.
His appearance came a day after Prime Minister Riad Hijab defected to the opposition.
Arriving in Damascus, Iran’s security chief Saeed Jalili said only a “Syrian solution” would end the crisis.
Iran is President Assad’s staunchest regional ally.
President Assad’s TV appearance was his first since 22 July – four days after a bomb killed four security chiefs in Damascus.
“Assad and Jalili discussed bilateral relations between Syria and the Islamic Republic of Iran as well as the situation in the region,” the TV report said.
Tehran says it is planning an international meeting on Syria on Thursday.
It is also trying to secure the release of a group of Iranians abducted by rebels from a bus in Damascus on Saturday.
As well as Mr Jalili’s visit to Damascus, Foreign Minister Ali Akbar Salehi is travelling to Turkey for talks in Ankara.
‘US held responsible’
An unconfirmed report from the rebels has suggested that three of the 48 hostages they are holding have been killed by army shelling.
Mr Jalili, who heads Iran’s supreme national security council and is considered a senior aide to Supreme Leader Ayatollah Ali Khamenei, had travelled to Damascus from Lebanon.
He told reporters that “kidnapping innocent people is not acceptable anywhere”, Iran’s official news agency Irna reported.
Iran’s Deputy Foreign Minister Hossein Amir Abdollahian has said it holds the US responsible for the hostages’ safety.
He said the US was supporting “terrorist groups” and despatching weapons to Syria, and was therefore responsible for the lives of those abducted.
Rebels say the group are members of Iran’s Revolutionary Guard. Tehran says they are pilgrims who had been heading for a Shia religious site.
‘Business as usual’
Syria’s caretaker Prime Minister Omar Ghalawanji headed an emergency cabinet meeting on Monday, stressing that all the ministers were there. He was due to chair a further session on Tuesday.
The BBC’s Jim Muir, in neighbouring Lebanon, said state media were giving the impression of it being business as usual in Damascus.
Opposition activists said that apart from the prime minister, two other ministers had also defected and a third – Finance Minister Mohammad Jalilati – was arrested as he tried to escape.
But footage of the cabinet on state TV showed two of the ministers who had supposedly defected and Syria’s information minister played down the significance of Mr Hijab’s departure.
“We haven’t heard anything from the former prime minister and he didn’t appear on TV,” Omran al-Zoubi was quoted as saying by state news agency Sana.
Syria was a state of institutions, the information minister said, and the flight of some of its individuals would not affect the state, however prominent they were.
But reports of defections have continued, with Turkey’s foreign ministry announcing on its Twitter feed that a general was among more than 1,300 refugees who fled across the border overnight.
The number of Syrians who have crossed into Turkey has risen to 47,500, Ankara says.
The UK said on Tuesday it was quadrupling its aid for refugees fleeing fighting in Syria.
‘Safe location’
Riad Hijab, appointed as prime minister less than two months ago, is the most prominent Syrian figure to defect so far.
Although his whereabouts are unclear, his spokesman appeared on al-Jazeera TV in neighbouring Jordan saying that the prime minister had fled Syria with his family and was in “a safe location”.
France said the Assad government was “doomed” and White House spokesman Jay Carney said such high-level defections signalled that President Assad’s grip on power was “loosening”.
On the ground in Syria, clashes have been reported in Aleppo and the army is said to have stepped up its bombardment of the northern city.
Government forces are trying to dislodge rebel fighters who say they control up to half of Aleppo.
Opposition activists report intense attacks on rebel-held areas on the north-east and south-west sides of the city.
State media said troops had clashed with “terrorists” in several places inflicting heavy losses.
Further deaths were reported in Damascus on Tuesday. State news agency Sana said a “terrorist hideout” had been stormed by security forces.
British-based activist group Syrian Observatory for Human Rights said 270 people were killed across Syria on Monday. It said 61 civilians died in Aleppo province alone.
Activists estimate more than 20,000 people have died since the uprising against President Assad began in March last year.