Syrian president to address nation amid clashes

Al-Assad's speech comes as fierce battles move closer to the capital, Damascus A rebel leader says the opposition is gaining ground Opposition: "International silence is only encouraging the regime to commit more crimes"

(CNN) -- Nearly two years into a gruesome civil war that has wrought bloodshed and misery across the country, President Bashar al-Assad will address his nation in a rare speech Sunday.

It's the first speech for the embattled president since June. Since then, tens of thousands of Syrians have been killed, and the country is no closer to a resolution.

But now, the battles between al-Assad's forces and rebels seeking his ouster are raging closer to the president's doorstep, with some of the fiercest fighting taking place near Damascus.

Al-Assad's speech is expected to touch on a recent meeting between the president, United Nations envoy Lakhdar Brahimi, U.S. Deputy Secretary of State William Burns and Burns' Russian counterpart Mikhail Bogdanov, according to Al-Akhbar, a Lebanese news agency that is known to support al-Assad.

During his last publicized speech in June, al-Assad called for unity.

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"We are in a state of real war, in every aspect of the words. And when we're in a state of war, all of our politics has to be concentrated on winning this war," al-Assad said at the time.

But the latest reports from inside Syria suggest rebels are gaining ground.

Opposition fighters chipped away at al-Assad's air power Saturday in the northwestern province of Idlib, where 800 rebels pummeled Taftanaz air base with anti-aircraft guns and tanks, a rebel leader said.

"The fight is closing in on them," rebel leader Capt. Islam Aloush said from Damascus. He said the head of the base was killed.

Al-Assad's forces use the base to launch helicopter attacks on nearby towns. Syrian warplanes dropped cluster bombs on Taftanaz in a raid that destroyed several buildings, the opposition Local Coordination Committees of Syria said Saturday.

Aloush said his militia and other groups want to target the many military bases in Idlib "to minimize the reach of the regime's warplanes," which opposition say attack civilians areas.

Opposition and government sources report that the extremist al-Nusra Front, which the United States has designated as a terrorist group with links to al Qaeda in Iraq, is taking part in the assault on Taftanaz.

Farther south in the Damascus suburbs, government forces have been cutting off food and medical supplies for weeks, Aloush said.

"They have sometimes resorted to field executions when they find people smuggling in syringes and other basic medical items," he said.

Other dissident groups have also reported the government ratcheting up the violence near the capital.

In an open letter Friday, Ahmed Moaz al-Khatib, head of the National Coalition of Syrian Revolutionary and Opposition Forces, implored the U.N. Security Council and world leaders to take action.

"Our people are subjected to genocide, and our country is being destroyed as the international silence is only encouraging the regime to commit more crimes against humanity," he wrote. "Halting massacres in Syria is an international obligation everyone should bear responsibility for."

More than 60,000 people have been killed across Syria since demonstrators protested against the Syrian government in March 2011.

CNN cannot independently confirm government or opposition reports out of Syria, as the government has restricted access by journalists.