Syrian activists say a bombing in the northwestern province of Idlib has killed 10 people, including nine members from the same family.

The Britain-based Syrian Observatory for Human Rights says at least two of those killed in Tuesday's attack were children. It is not yet clear who was behind the mortar bombings.

The news comes a day after Syrian activists said a double bomb attack near security buildings in the northwestern town of Idlib killed at least 20 people.

The activists said the attack in Idlib targeted intelligence offices used by the Syrian army and air force. Syria's state news agency said suicide bombers triggered the blasts. The news agency gave a lower death toll of at least nine, with another 100 people wounded.

Casualties could not be independently confirmed.

A small team of unarmed U.N. soldiers began operating in Syria earlier this month to monitor a shaky truce agreement in the Syrian conflict, which has lasted more than a year.

The Syrian government and rebels accepted a U.N.-backed truce agreement that took effect on April 12. But forces loyal to Syrian President Bashar al-Assad have continued assaulting opposition hubs, while rebel fighters have repeatedly ambushed government security personnel. Each side accuses the other of provoking attacks.

The cease-fire agreement is part of a peace plan mediated by international envoy Kofi Annan.

The United Nations estimates that at least 9,000 people have been killed since Mr. Assad began cracking down on the uprising in March 2011.