Syrian President Bashar Assad issued a decree Sunday granting amnesty and reducing sentences for all crimes committed before Sept. 14, state news agency SANA said.

Similar amnesties have been issued on several occasions most recently last year since Syria's crisis began in March 2011.

According to Sunday's pardon, life-long terms would replace death sentences, and a 20-year-long sentence at hard labour would replace life-long sentences at hard labour, and a 20-year sentence would replace long-life sentences.

Prisoners with incurable diseases including cancer would be freed, it said.

The decree stipulated granting a general amnesty for military deserters who turn themselves in within 3 months for those inside the country, and 6 months for those outside the country.

Also Sunday, Assad received Russia's Special Envoy to Syria Alexander Lavrentiev and its Deputy Foreign Minister Sergey Vershinin, a day before a trilateral summit in Turkey that will include the leaders of Russia, Turkey and Iran in which Syria will be the main focus of talks.

Monday's summit in the Turkish capital of Ankara will discuss the situation in the northwestern province of Idlib that has been under attack by government forces since April 30. A truce has been holding despite some violations since the end of August.

Russia and Iran are strong backers of Assad while Turkey supports the Syrian opposition.

SANA said Lavrentiev briefed Assad on the agenda of the summit.

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Separately in northern Syria, a car bomb killed at least eight people and wounded seven others in a town held by Turkey-backed opposition fighters, Syrian opposition activists said.

The Britain-based Syrian Observatory for Human Rights and Thiqa news agency, an activist collective, said the blast occurred Sunday night in the town of Rai.

There was no immediate claim of responsibility for the bombing near the town's entrance, the second such deadly blast in the wider rebel-held area since June.

A member of the rebel security forces, Osama Abu al-Kheir, told AFP that a refrigerator truck blew up outside a healthcare centre.