BEIRUT: A series of blasts rocked Syria's capital and the northern commercial hub of Aleppo on Saturday, killing at least five civilians in the second city, said the Syrian Observatory for Human Rights.

One explosion in Aleppo went off in a car wash just as a bus was passing by in Tal al-Zarazir district, the Observatory's Rami Abdel Rahman said.

Two blasts also hit the capital Damascus, Abdel Rahman told AFP in Beirut.

“One explosion occurred inside the city, and the other hit the periphery,” he said.

One of the Damascus blasts appeared to target a bus transporting regime troops, said Abdel Rahman.

“At least three regime troops were wounded,” he added.

The other Damascus explosion caused no casualties, according to the Observatory.

Also in Damascus, regime troops opened fire in the central neighbourhood of Barzeh, as they carried out multiple raids and made arbitrary arrests in the capital, the watchdog said.

Abdel Rahman, speaking on the phone from Britain, accused the government of carrying out the Damascus bombings to prevent people attending funerals for nine civilians killed in the Syrian capital on Friday.

The nine died during demonstrations and funerals in the neighbourhoods Kfar Sousa and Tadamon.

“This is the highest death toll we have seen inside Damascus” since a ceasefire took hold in April 12, added Abdel Rahman, whose group says more than 600 people have been killed nationwide during the tenuous truce.

Opposition bloc the Syrian National Council, in a statement on Saturday, called on the UN observers to visit Kfar Sousa and Tadamon, “where the funerals of the martyrs killed Friday will be held.”

The peace agreement was brokered by UN-Arab League envoy Kofi Annan, whose office said Friday that his plan was “on track.”