In a valley tucked away behind the mountains just to the north of Damascus, Free Syrian Army rebels are gathering their strength and preparing for what they hope will be a final assault on the capital.

They may have to wait longer than they had hoped.

The bomb that killed four top aides to President Bashar al-Assad last week provided a huge boost to the morale of the loosely organized rebel movement here and across the country, triggering a surge of fighting nationwide as rebels sought to benefit from the disarray in the capital.

Five days later, however, it is becoming clear that the eruption of violence in Damascus may have been just another battle in what still could be a protracted war. On Monday, Syrian troops moved house to house in neighborhoods that had briefly fallen under rebel control, breaking down doors and detaining suspected opposition sympathizers. State television broadcast pictures of the bodies of dead fighters, of handcuffed, blindfolded prisoners and of soldiers sweeping through fields on the edge of the city hunting down “terrorists,” as the government calls the rebels.

In the first public comments by a Syrian official since the day of the attack, Foreign Ministry spokesman Jihad Makdissi said at a news conference in Damascus that the government has regained the upper hand. “The security situation will be under control in one or two days,” he said in remarks broadcast live by state television.

He also warned the international community not to attempt to intervene militarily, pledging that Syria would not use chemical weapons against its people but would use them in the event of a foreign attack.

“These weapons are stored and secured by Syrian military forces and under its direct supervision, and will never be used unless Syria faces external aggression,” he said.

The threat comes after widespread reports that the United States and its allies are preparing contingency plans to secure Syria’s arsenal of chemical weapons should the chaos worsen. Other reports have said that the Syrian government recently moved some of its stockpiles, either with a view to using them or to prevent them from being seized by rebels.

Makdissi’s appearance suggested the government is recovering its balance after the biggest shock to its cohesion since the uprising against President Bashar al-Assad’s rule began 16 months ago.

Col. Malik Kurdi, spokesman for the Free Syrian Army command, said the rebels had no choice but to pull out of the Damascus neighborhoods they seized last week, because they lack the weapons to confront the better-equipped regular army.

“The Free Syrian Army is carrying out a war of harassing the regime army until it is exhausted, using guerrilla tactics,” he said, speaking by telephone from the military refugee camp in southern Turkey where the rebel leadership is based. “We can’t keep control of an area, so this is a circular operation, moving from one place to another, one city to another, to tire the regime out.”

Events in al-Tal, an upmarket suburb nine miles north of the capital, followed a pattern seen in many parts of the country in the wake of the bombing, with rebels launching attacks against government positions in an attempt to seize the initiative. Acting on orders they said they received from Free Syrian Army headquarters, the rebels in al-Tal stormed two government buildings, detained more than 40 soldiers and regime supporters, and seized a significant amount of weapons.

The rebels might be outgunned, but it is clear they are learning how to use the weaponry they have effectively. Two burned-out tanks loll in the road, evidence of an unsuccessful government reinforcement attempt during the battle. One had its turret blown off, the result of a rocket-propelled grenade shot that was either very skilled or very lucky. Fighters said eight other tanks retreated after the lead tanks were destroyed.

The rebels are taking shifts guarding newly captured checkpoints that ring the town, watching and waiting for the reinforcements they have been told are coming to help with the final push on Damascus.

“Every day, more are coming, from all the towns to the north,” said a fighter at one checkpoint who identified himself as Abu Zaid. He predicted that the rebels could be ready for an offensive as early as next week. “Bashar al-Assad will be killed in Damascus soon,” he said.

But their hold on al-Tal was challenged that afternoon by two artillery shells that crashed into the center of town. Residents gathered to survey the damage from what they said were the first artillery rounds to hit al-Tal.

Fighting continued in other parts of the country even as the army was mopping up in Damascus, with rebels claiming to be gaining ground in the northern city of Aleppo. Residents said that the clashes had not yet reached the commercial center of Syria’s biggest city but that the battles in outlying neighborhoods could be heard clearly.

The rebels have made significant gains in northern rural areas of the country in recent months, but even there the battle lines are fluid, and towns and villages frequently change hands. Kurdi, the Free Syrian Army spokesman, pointed to the rebels’ recent capture of a number of border posts, some of which have changed hands several times in the past four days, notably the Bab al-Hawa crossing on the Turkish border.

“We do not keep control of crossings and checkpoints. We controlled Bab al-Hawa, then we pulled out, then we controlled it again, and so it goes on,” he said. “We cannot say the Free Syrian Army is in complete control, and we cannot say the regime army is in complete control, and this will stay the same until the Free Syrian Army gets heavy weapons and there are more defections.”

Sly reported from Antakya, Turkey. Suzan Haidamous contributed from Beirut.