Syrian rebels say they have brought down a fighter jet near the town of Atarib in Aleppo province, in video obtained by the Reuters news agency, as the commander of the country's main rebel group said was moving its command centre from the Turkish border into Syria.
Reuters could not confirm the authenticity of the video in which rebels also appeared to have surrounded a military building near the town of Awrem, said to be loyal to President Bashar al-Assad's government.
"God's willing the building 46 has been attacked which is located near Awrem. God also helped us and we brought
down a Mig warplane," one rebel was reported as saying by the news agency on Saturday.
"So many groups took part in the attack. Most of the brigades in the area participated in this operation.''
The video also purports to show an attack on the headquarters of regiment 46 near Atarib.
A witness, an independent journalist who asked to remain anonymous, said that rebel fighters were attacking a military base near the town when the jet flew over and rebels shot it down with anti-aircraft guns.
Al Jazeera's Nacer El-Bedri, reporting from Aleppo, said the attack by one of the main brigades of the Free Syrian Army (FSA) took place around 6am, local time on the western side of Aleppo.
"The attack took place against the regiment 46 which is one of the last outpost regiments based in the city of
Aleppo, which is one of the elite, special forces.
"They surrounded the base and they attacked it by RPG [Rocket Propelled Grenade] - by morter, and the Syrian Free Army claim that they managed to overrun and take control of the base.
"The information that we have is that they have managed to inflict heavy damage onto on the outpost and surrounding check points, but we have no confirmation that they have been able to outrun it," said our correspondent.
"It seems from the bombing that followed, in the surrounding areas, by the artillery and by aircraft, that a serious blow was inflicted by the Free Syrian Army on the Syrian government's army in the region."
The government force seems and looks overstretched in the number of frontlines that they are fighting and the FSA seems to have the upper hand, and to gain streets and districts day by day, said our correspondent.
Shift of command centre
In another development, the FSA said on Saturday it was moving its command centre from the Turkish border into Syria itself in preparation of an offensive against Assad's troops in Damascus.
Riyad al-Asaad, commander of the Free Syrian Army (FSA), announced the move on Saturday in a video message from Syria, the first since the group founded its command centre in Turkey at the beginning of the 19-month conflict.
"To the Syrian people, its freedom fighters and all the armed factions, we are glad to let you know that the leadership of the FSA has moved into Syria following arrangements made with other brigades that included securing liberated areas with the hope of launching the offensive on Damascus," Asaad said.
He said the FSA has felt pressure by the international community to take a leading role in post-war Syria. Asaad said the FSA rejected those offers, reiterating that the people of Syria should decide the future of the country.
"Since we left our country we suffered all sorts of regional and international interference and political pressure, we were isolated.
"Their goal was to have the FSA replace Assad once he is gone, but we categorically made it clear that we would never betray our people reiterating that only the Syrians should decide their future institutions.”
Al Jazeera's Andrew Simmons, reporting from Akcakale on the Turkey-Syria border, said the rebels have been cautiously edging forward, taking territory 5km inside Syria.
"The move of the command centre is not necessarily a massive breakthrough because the FSA is still very much dependent on Turkey for its supply lines," he said.
In other developments on Saturday, Syrian government troops and rebels clashed near a border crossing with Jordan, opposition activists said.
Al Jazeera's Hashem Ahelbarra discussed challenges for the Free Syrian Army despite its alleged gains
The fighting, accompanied by heavy shelling from government troops, raged on Saturday near the busy Al-Nasib border crossing located on a highway linking the Syrian and Jordanian capitals, according to the activists.
Egyptian Middle East News Agency (MENA) quoted a high-ranking Jordanian official as denying the reports about clashes between Jordanian and Syrian armies.
The official confirmed that Jordanian soldiers shot in the air to distract the Syrian soldiers from chasing refugees during their attempts to cross the border.
Vastly outgunned, rebels say they need surface-to-air missiles to take down fighter jets and helicopters used by the Syrian military to bombard opposition strongholds.
Fighters use outdated anti-aircraft machine guns that are welded to pickup vehicles but they are inaccurate and useless if the military aircraft fly above a certain altitude.
On August 27 fighters shot down a helicopter on the outskirts of Damascus and three days later rebels said they had brought down a jet in Idlib, near the Turkish border.
Elsewhere in Syria, activists said government jets bombarded areas in Yabroud, near the capital Damascus, and pro-rebel districts in the embattled northern city of Aleppo.
In-depth coverage of escalating violence across Syria
Independent verification of reports out of Syria is constrained by media restrictions imposed by the government in Damascus.
At least 150 people, mainly near Damascus and Aleppo, were killed across Syria on Friday, the opposition Syrian Observatory for Human Rights reported.
Also on Friday, Iraq has barred a North Korean aircraft from using its airspace on suspicion it was carrying weapons for Syria, regional media reported.
Earlier this week, US officials accused Iraq of allowing Iran to fly arms to Syria using the Iraqi airspace, a charge denied by the Baghdad government. North Korea and Iran are allies of Assad.
Activists say more than 27,000 people, mostly civilians, have been killed in the uprising in Syria, which began with peaceful street protests that provoked a military crackdown and mushroomed into civil war.
Despite calling for Assad to step down, the West is wary of arming disparate rebel groups.