Syrian state media say two bombs have exploded near a security compound in Damascus, wounding four people in an attack claimed by Free Syrian Army rebels.

State media denounced Sunday's bombings in the Abu Rummaneh district of the capital as an act of terrorism.

In another attack, the Syrian government said a car bomb exploded in a Damascus suburb late Saturday, killing 15 people. The Syrian capital and its suburbs have seen a series of bombings in recent months, mostly targeting the security establishment of President Bashar al-Assad.

Syrian opposition activists said Mr. Assad's forces bombarded rebel-held areas of several provinces on Sunday. Syria's uprising began in March 2011 with peaceful protests against the president's autocratic rule but escalated into a civil war as he tried to crush opponents with deadly force.

New international peace envoy Lakhdar Brahimi said Saturday change in Syria is “necessary, indispensable and unavoidable.” But in an interview with Arab television network Al Jazeera, he also said it is “too early to speak about who should go and who should stay.” Western powers and their Arab allies have demanded that Mr. Assad step down, but Russia, China and Iran have rejected such calls as interference in Syrian affairs.

Brahimi, a former Algerian diplomat, assumed the post of U.N.-Arab League envoy on Saturday, after his predecessor Kofi Annan quit in frustration as Syria's fighting escalated.

The new envoy said he will speak to Mr. Assad to try to resolve the conflict and insisted such a move “is not a step backwards.” Before resigning, Mr. Annan said the Syrian president “must leave office.”