IDLIB, Syria — Syria's conflict heated up Tuesday with rebels battling the regime's elite Republican Guard forces in the suburbs of the capital, Damascus, as Turkey's prime minister threatened to defend his country's territory from Syrian military encroachments in response to the nation's downing of a Turkish war plane Friday.
The increasingly fierce fighting prompted Syrian President Bashar Assad to declare that the country is "in a state of war," while the White House remarked that Mr. Assad has been slowly "losing his grip over the country" during the 16-month-old Arab Spring uprising against the regime.
"When one is in a state of war, all our policies and capabilities must be used to secure victory," Mr. Assad told his Cabinet, according to the official Syrian Arab News Agency.
White House spokesman Jay Carney said Mr. Assad is desperate to hold on to power as his beleaguered regime slowly gives way.
"I would note that recent high-level military defections to Jordan and Turkey are another testament to the regime's loss of control over the situation in Syria," Mr. Carney said on Air Force One as President Obama flew to a campaign event in Atlanta, the Associated Press reported.
Meanwhile, Syrian activists - who estimated that 116 people were killed Tuesday and more than 14,000 have died since the uprising started - said the failure of the international community's peace efforts forced opposition fighters to go all out in attacking the heart of the regime.
"Before, the Free Syrian Army was trying to abide by [U.N. envoy] Kofi Annan's peace plan," said Abdulwahab Sayed Omar, a Syrian opposition activist based in the United Kingdom.
"Now that the peace plan is nothing more than a part of Syria's modern history, the Free Syrian Army is trying to flex its muscles, to show that nowhere is safe for any of those generals or military units that stand side-to-side with Assad."
Defectors from the Syrian army described how they had been instructed to identify themselves as police officers to U.N. monitors to show that the regime had been following Mr. Annan's six-point plan of removing the military from urban areas.
"When the U.N [Supervision Mission in Syria] came to our area, we were all given police ID cards and a sheet of paper with answers to the questions the U.N. would ask," a defecting Syrian soldier said Tuesday. "My entire military battalion was turned into a police force - on paper."
The opposition's strength - symbolically at least - was boosted in recent days by a fresh raft of defections from the regime forces by high-level military personnel. Activists said at least 33 left Syria for Turkey, taking their families with them.
"Every single defection boosts the morale and the capacity of the Free Syrian Army," Mr. Omar said.
Activists said there is a lot of sympathy for the opposition among high-level figures in Syria's army and that a larger number would defect if the protection of the defectors' families could be guaranteed.
In Turkey, Prime Minister Recep Tayyip Erdogan made a televised address in which he stressed that his nation would not tolerate any encroachments or attacks by Syrian forces, signaling an escalation in aggression between the neighboring countries.
"Any military element that approaches the Turkish border from Syria and poses a security risk and danger will be regarded as a threat and treated as a military target," Mr. Erdogan said Tuesday.
Turkey has allowed the Free Syrian Army to use its territory close to the Syrian border to set up base camps and regroup, and the Syrian National Council - composed of opposition leaders and defectors - has headquarters in Istanbul.
"Turkey is running the Syrian opposition off its soil," said Joshua M. Landis, director of the Center for Middle East Studies at the University of Oklahoma. "It's helping them get armed, funding and spearheading the effort to bring down the Assad regime - and it will probably succeed."
Mr. Landis also suggested that NATO may have been complicit in Turkish reconnaissance missions across the border. Syria shot down a Turkish reconnaissance plane Friday, saying it was in Syrian airspace. Turkey has said the plane was in international airspace and its pilots have not been found.
"Turkey has undoubtedly been probing Syrian airspace trying to test their defenses, trying to find out where their radar is," Mr. Landis said. "I would presume that Turkey is doing this kind of thing and that NATO is mapping where Syrian defenses are and how good they are, how alert they are.
"Eventually, Syria got tired of this probably and they whacked one of these airplanes."
Still, any direct foreign military intervention in Syria remains unlikely. Analysts say that with a far stronger military, Turkey is in no need of defense from Syria. So far, the U.N. response has been limited to placing sanctions on the Assad regime.
"The U.N. will let things stew," Mr. Landis said. "Enough progress is being made by the opposition. The Syrian government are becoming more and more beleaguered, while the opposition is growing in strength all the time."
c Ruby Russell reported from Berlin.