BEIRUT – Two booby-trapped vehicles exploded within hours of each other Friday in Syria’s once-impregnable capital of Damascus, killing at least five police officers as rebels increasingly target President Bashar Assad’s seat of power.

Elsewhere in Damascus, shells struck a Palestinian refugee camp, killing 10 people, state media said.

The uprising began in March 2011, when protests calling for political change were met by a violent government crackdown by government troops. Many in the opposition took up arms, and activists say more than 23,000 people have been killed. The government says more than 4,000 security officers are among the dead.

Damascus was relatively quiet until July, when rebels launched a bold attack, capturing several neighborhoods and setting off a bomb that killed four high-ranking security officials, including the defense minister and Assad’s brother-in-law.

Since then, the regime has succeeded in largely quelling a rebel offensive in the capital, but has struggled to contain an opposition push into the northern city of Aleppo, the country’s commercial hub.

Friday’s first blast in Damascus killed five officers when a motorcycle packed with explosives blew up across the street from a mosque in the Rukneddine neighborhood, state TV said.

There were no casualties in the second blast, a car bomb that went off about two hours later in the upscale Mazze neighborhood near the Ministry of Information and the Ministry of Justice, which are about 330 feet apart. Friday is the weekend in Syria and institutions are usually closed.

Fruit peddler Walid Mahmoud said he was about 165 feet away from the first explosion.

“It was thunderous, and if I was closer, I would have been killed,” he said. “I saw many bodies on the ground.”

State TV blamed terrorists, the term the regime uses to describe the rebels.

The blasts came five days after two bombs exploded near the offices of the Syrian military’s joint chiefs of staff in Damascus, slightly wounding four officers.

Peter Maurer, the new president of the International Committee of the Red Cross who just returned from a three-day trip to Syria, said he was shocked by the “immense destruction” he saw there.

“Since the conflict erupted, there have been many casualties, and now the situation is rapidly deteriorating even further,” Maurer said in Geneva on Friday.