Syrian government forces are reported to be preparing for a major offensive on rebel-held parts of the northern city of Aleppo and its surroundings.
A security source said it would start "in the coming hours or days", echoing a pro-government newspaper article saying troops were "deploying heavily".
Activists said there were no signs yet of a renewed push on the Aleppo.
The development comes only days after government forces backed by Hezbollah fighters recaptured the town of Qusair.
On Sunday, they retook the last remaining rebel-held villages in the strategically important area, which lies between the Lebanese border and the central city of Homs.
'On the offensive'
Much of northern Syria has been controlled by rebel groups since last year and the frontlines inside Aleppo have been largely static for months.
However, the fall of Qusair on Wednesday to troops and militants from Hezbollah, the Lebanese Shia Islamist movement, has reportedly been seized on by the military's leadership as a decisive victory.
An article in the pro-government Syrian newspaper, al-Watan, said the army was now "deploying heavily in the countryside near Aleppo in preparation for a battle that will be fought inside the city and on its outskirts".
"Besieged areas will be freed in the first stages and troops which have been on the defensive will go on the offensive."
It added: "The Syrian army will take advantage of its experience in Qusair and Eastern Ghouta [near Damascus] to advance in the provinces of Hama and Homs."
A security source also said the government's next target was Aleppo.
"It is likely the battle for Aleppo will start in the coming hours or days, and its aim is to reclaim the towns and villages in the province," the source told the AFP news agency.
The planned offensive is reportedly named "Operation Northern Storm".
Opposition activists said they had not seen any significant troop build-up outside Aleppo, but fierce fighting was reported on Sunday in Nubbul and Zahra, two villages on the outskirts of the city that are predominantly Shia Muslim.
A rebel commander and former senior military officer, Brig Gen Mustafa al-Sheikh, said the government had been using helicopters to reinforce its positions with loyalists, including Hezbollah fighters and Shia from Iraq.
"The [army's] aim is to use the two villages as forward bases to make advances in Aleppo and its countryside," he told the Reuters news agency.
"The regime considers that it has received a shot in the arm after the Qusair battle, but they will find that it will not be easy to advance in Aleppo."
Local activist Abu Mujahid said troops backed by Hezbollah militants had attempted to break a rebel siege of a military airport in the town of Minnig, near Zahra and Nubbul, and that the rebels were monitoring activity at the nearby Salamiya army base.
Hezbollah's leader, Hassan Nasrallah, declared at the end of May that the group had sent fighters to Syria to assist forces loyal to President Bashar al-Assad, and vowed to fight to the end to defeat the rebellion and defend Lebanon from jihadist extremists.
In a separate development on Sunday, the Syrian Observatory for Human Rights reported that Islamist rebels in Aleppo had executed a 15-year-old boy in front of his parents as punishment for what they regarded as a blasphemous comment.
The UK-based activist group said Mohammed Qataa was shot in the face and neck a day after being seized by the rebels, who allegedly overheard the teenager tell someone: "Even if the Prophet Muhammad comes down [from heaven], I will not become a believer."
Before executing the boy, one of the rebels reportedly told onlookers: "Disbelieving in God is polytheism and cursing the Prophet is polytheism. Whoever curses even once will be punished like this."
The SOHR published a photograph of what it said was the boy's face, which bore gunshot wounds to the mouth and neck. Its director, Rami Abdul Rahman, said it could not "ignore these crimes, which only serve the enemies of the revolution and the enemies of humanity".