'Deadly car bomb' explodes in Syrian city of Aleppo
A car bomb has exploded in the northern Syrian city of Aleppo, killing at least two people and injuring 30 others.
Officials blamed terrorists for the attack, which state media said killed a policeman and a female civilian.
Syrian TV showed a wrecked apartment block and rubble strewn across a street in Aleppo, which last suffered a deadly bomb attack in early February.
It comes a day after two car bombs blew up near security buildings in the capital Damascus, killing 27.
The government routinely blames terrorists for bomb attacks, and links them to the year-long uprising against the rule of President Bashar al-Assad.
The opposition, however, has accused the authorities of staging some of the bombings to characterise the rebels as terrorists.
Details of the reports are difficult to verify as foreign journalists are heavily restricted in Syria.
Elsewhere, activists said at least 16 people had been killed by security forces around the country on Sunday.
The BBC's Lina Sinjab in Damascus says both Damascus and Aleppo are seen as cities with high levels of support for President Assad.
She says both cities have been under tight security control to prevent mass opposition protests like those in Homs and Idlib.
Meanwhile leaders of an opposition group were arrested after trying to organise anti-government protests in Damascus.
Our correspondent says it is unusual as the group, the Syrian National Coordination Council, is tolerated by the authorities and had announced its demonstration beforehand.
Meanwhile, diplomatic efforts to get aid into the country are continuing, with Red Cross chief Jakob Kellenberger visiting Russia to highlight their concerns.
The Red Cross said in a statement that Mr Kellenberger would visit Foreign Minister Sergei Lavrov on Monday to press for an "unambiguous commitment" for daily halts in fighting to allow aid to be delivered.
Russia is seen as the only nation with real influence over the regime in Damascus.
The Aleppo attack was near a security building in the Suleimaniyeh quarter of the city, London-based opposition group the Syrian Observation for Human Rights said.
The group quoted residents as saying they heard a heavy blast in the early afternoon and later saw bodies in the streets.
A resident told the Associated Press news agency the affected area had a large Christian population and was generally crowded on Sundays.
"It was a strong explosion. It shook parts of the city," Mohammed Saeed said. "White smoke was billowing from the area."
State media said the attack took place near a post office and between two buildings in a residential area.
The latest blasts have come within days of the first anniversary of the uprising against Mr Assad, which UN estimates say has left more than 8,000 people dead.
UN and Arab League envoy Kofi Annan has announced he is sending a team to Damascus to discuss setting up a new international monitoring mission.
On Friday he renewed calls for an end to fighting and for unimpeded humanitarian to be sent to Syria.
President Assad insists his troops are fighting "armed gangs" seeking to destabilise Syria.