Two car bomb explosions in the central Syrian city of Homs have left at least 12 people dead and dozens of others injured, medics reported.

Sunday's blasts occurred in al-Malaab neighborhood, an upscale government-controlled area in the center of Homs.

Security forces surrounded the area and state-sponsored television arrived to film the scene.

Al-Malaab, where many cafes and restaurants are located, has seen frequent anti-government protests and ensuing crackdown by security forces. It has also been hit by deadly stray mortar rounds on several occasions since the uprising in the country began in March last year.

It currently houses hundreds of displaced people who fled their homes in violence-hit areas of the city where opposition strongholds have been shelled by government forces.

Meanwhile, Syrian opposition forces opened fire on a Lebanese army base in Lebanon's Bekaa Valley on Sunday. The Lebanese troops shot back, according to an army statement. No casualties were reported.

Damascus violence

Elsewhere in the country, clashes raged on Sunday as government forces hammered opposition positions around Damascus with artillery and air raids, as part of an offensive aimed at securing the capital, activists said.

The army also reportedly pounded the Damascus district of Kafr Souseh as it tried to block opposition forces from reaching the capital via its southwestern entrance.

Forces loyal to President Bashar al-Assad have been trying to establish a secure perimeter around Damascus at all costs, turning the province into one of the main battlegrounds in the country's 20-month conflict.

The latest reports of violence came a day after Syria's internet connections were restored on Saturday after a two-day blackout, the worst communications outage since the uprising began.

The internet was back in most parts of the country, including in Damascus, the northern city of Aleppo, the central cities of Homs and Hama, and the coastal city of Tartus, residents in the areas told Al Jazeera.

Renesys, a US-based firm that monitors online activity, confirmed a "largely complete" restoration of internet service in Syria.

Experts said the outage was highly likely to have been caused by the state.

Assad's government has previously been accused of cutting internet and telephone connections to block communications of activists and opposition.

Authorities had attributed the latest outage to a "terrorist" attack or a technical fault. The government frequently uses the term terrorist to describe opposition fighters.

Russia-Turkey talks

In a separate development, Russian President Vladimir Putin heads to Turkey on Monday for a one-day trip focused on trade that is likely to be overshadowed by the two countries' differences over Syria.

During the talks, Turkey is certain to press Putin to stop backing Syrian President Bashar Assad.

The Kremlin, however, has shown no inclination of relinquishing its support for its last Mideast ally, whom it has shielded from international sanctions and continued to provide with weapons amid an escalating civil war.

Russia and China have used their veto power at the UN Security Council to block any UN sanctions on Assad's regime over its crackdown on an uprising that began in March 2011.

Advocates say at least 40,000 Syrians have been killed in the fighting since then.

Moscow also has insisted that it would honor weapons contracts signed earlier with Syria for the delivery of anti-ship and air-defense missiles.

The Kremlin has argued that the Russian arms sales don't violate any international agreements and has rebuffed Western demands to halt the trade.

Russia reacted angrily in October when Turkey forced a Syrian passenger plane flying from Moscow to land in Turkey due to what Turkish officials said was military equipment on board. Moscow said the plane was legally carrying radar parts for Syria.

PHOTO CAPTION

Al-Malaab neighborhood, which contains many cafes and restaurants, has seen frequent anti-government protests

Aljazeera