Syrian warplanes bombed insurgents east of Damascus on Saturday and government forces pounded a town to the southwest, activists said, in a month-long and so far fruitless campaign to dislodge rebels around the capital.
Jets bombarded the Beit Sahm district on the road leading to the international airport and the army fired rockets at several rebel strongholds around Damascus, President Bashar al-Assad's bastion through 21 months of an increasingly bloody uprising.
The 47-year-old Alawite leader, forced on the defensive by the mainly Sunni Muslim rebels, has resorted increasingly to air strikes and artillery to stem their advances on the ground.
NATO's U.S. commander also accused his forces on Friday of firing Scud missiles that landed near the Turkish border, in explaining why the Western alliance was sending anti-missile batteries and troops to Syria's northern frontier.
The Syrian government denies firing such long-range, Soviet-built rockets. But Admiral James Stavridis wrote in a blog that a handful of Scud missiles were launched inside Syria in recent days towards opposition targets and "several landed fairly close to the Turkish border, which is very worrisome".
It was not clear how close they came. Turkey, a NATO member once friendly toward Assad but now among the main allies of the rebels, has complained of occasional artillery and gunfire across the border, some of which has caused deaths, for months. It sought the installation of missile defenses along its frontier some weeks ago.
"Syria is clearly a chaotic and dangerous situation, but we have an absolute obligation to defend the borders of the alliance from any threat emanating from that troubled state," Stavridis wrote.
Batteries of U.S.-made Patriot missiles, designed to shoot down the likes of the Scuds popularly associated with Iraq's 1991 Gulf War under Saddam Hussein, are about to be deployed by the U.S., German and Dutch armies, each of which is sending up to 400 troops to operate and protect the rocket systems.
Damascus has accused Western powers of backing what it portrays as a Sunni Islamist "terrorist" campaign against it and says Washington and Europe have publicly voiced concerns of late that Assad's forces might resort to chemical weapons solely as a pretext for preparing a possible military intervention.
In contrast to NATO's air campaign in support of Libya's successful revolt last year against Muammar Gaddafi, Western powers have shied away from intervention in Syria. They have cited the greater size and ethnic and religious complexity of a major Arab state at the heart of the Middle East - but have also lacked U.N. approval due to Russia's support for Assad.
As well as the growing rebel challenge, Syria faces an alliance of Arab and Western powers who stepped up diplomatic support for Assad's political foes at a meeting in Morocco on Wednesday and warned him he could not win Syria's civil war.
Assad's opponents have consistently underestimated his tenacity throughout the uprising, but their warnings appeared to be echoed by even his staunch ally Moscow when the Kremlin's Middle East envoy Mikhail Bogdanov conceded he might be ousted.
Russia said on Friday Bogdanov's comments did not reflect a change in policy. France, one of the first countries to grant formal recognition to Syria's political opposition, said Moscow's continued support for Assad was perplexing.
"They risk really being on the wrong side of history. We don't see their objective reasoning that justifies them keeping this position because even the credible arguments they had don't stand up anymore," a French diplomatic source said, arguing that by remaining in power, Assad was prolonging chaos and fuelling the radicalization of Sunni Islamist rebels.
European Union leaders who met in Brussels on Friday said all options were on the table to support the Syrian opposition, raising the possibility that non-lethal military equipment or even arms could eventually be supplied.
In their strongest statement of support for the Syrian opposition since the uprising began, EU leaders instructed their foreign ministers to assess all possibilities to increase the pressure on Assad.
With rebels edging into the capital, a senior NATO official said that Assad is likely to fall and the Western military alliance should make plans to protect against the threat of his chemical arsenal falling into the wrong hands.
Desperate food shortages are growing in parts of Syria and residents of the northern city of Aleppo say fist fights and dashes across the civil war front lines have become part of the daily struggle to secure a loaf of bread.
Foreign Minister Walid al-Moualem told U.N. humanitarian chief Valerie Amos that U.S. and EU sanctions on Syria were to blame for hardships in his country and urged the United Nations to call for them to be lifted.
Moualem also called on the United Nations to expand its relief efforts in Syria to include reconstruction "of what has been destroyed by the armed terrorist groups", the state news agency SANA said, using a label employed by authorities to describe the rebels.
Amos said in Rome on Friday the United Nations is committed to maintaining aid operations in Syria.
The World Food Programme (WFP) says as many as a million Syrians may go hungry this winter, as worsening security conditions make it harder to reach conflict zones.
"NOTHING OFF THE TABLE"
At the EU summit, Britain's David Cameron pushed for an early review of the arms embargo against Syria to possibly open the way to supply equipment to rebels in the coming months. Germany and others were more reluctant and blocked any quick move. But there was widespread agreement that whatever action can be taken under current legislation should be pursued, and the arms embargo would still be reviewed at a later stage.
"I want a very clear message to go to President Assad that nothing is off the table," Cameron told reporters at the end of the two-day meeting. "I want us to work with the opposition ... so that we can see the speediest possible transition in Syria.
"There is no single simple answer, but inaction and indifference are not options."
Forty thousand people have now been killed in what has become the most protracted and destructive of the Arab popular revolts. The Assad government severely limits press and humanitarian access to the country.
Among factors holding Western powers back from arming the rebels is the presence in their ranks of anti-Western Islamist radicals. Following a U.S. decision this week to blacklist one such group, Jabhat al-Nusra, as "terrorist", thousands of Syrians demonstrated on Friday against ostracizing it.