BEIRUT -- Syrian President Bashar Assad urged his armed forces Wednesday to step up the fight against rebels as the U.N. reported a significant escalation in the civil war with the military using warplanes to fire on opposition fighters in the battle for Aleppo.
Sausan Ghosheh, the spokeswoman for the U.N. mission in Syria, said that international observers had witnessed warplanes firing in Syria's largest city, where intense fighting has been raging for 12 days. She said the situation in Aleppo was dire, with "heavy use of heavy weapons" including tanks, which the rebels now possess as well.
"Yesterday, for the first time, our observers saw firing from a fighter aircraft. We also now have confirmation that the opposition is in a position of having heavy weapons, including tanks," she said, adding that for civilians, there "is a shortage of food, fuel, water and gas."
Residents of Aleppo have told The Associated Press over the past week that jet fighters have been strafing rebel positions and there are numerous videos on the Internet posted by activists showing rebels commandeering regime tanks after conquering their bases.
Aleppo, a city of some 3 million, has been wracked by violence since rebels attempted to take it over and succeeded in holding several neighborhoods despite daily assaults by regime tanks, helicopters and warplanes.
On the 67th anniversary of the Syrian army's founding, Assad pushed his armed forces to redouble their efforts in the fight in a speech that was not televised but only appeared in the army's magazine.
"Today you are invited to increase your readiness and willingness for the armed forces to be the shield, wall and fortress of our nation," he said.
The regime has characterized the rebellion as the work of foreign terrorists, and Assad claimed "internal agents" are collaborating with them.
"Our battle is against a multi-faceted enemy with clear goals. This battle will determine the destiny of our people and the nation's past, present and future," he said.
Assad has not spoken in public since a bomb on July 18 killed four of his top security officials during a rebel assault on Damascus and has only appeared on television once. His whereabouts are unknown and it is not even clear if he is in the capital.
Syria's powerful military, which has largely held together over the course of the uprising, is vital to keeping Assad in power. The pace of defections has been rising recently, however. Neighboring Turkey reports that 28 generals have already crossed the border.
In recent weeks, the military has unleashed heavy weapons against the increasingly bold rebels who have brought the fight to the country's two largest cities. The military managed to drive the rebels out of the capital Damascus a week after their assault with fierce bombardments of neighborhoods followed by house-to-house searches.
Minor clashes with the rebels around Damascus continue, however, and in the early hours of the morning Wednesday residents of the Christian neighborhood of Bab Touma in Damascus' old city reported a half-hour gun battle.
There was also ongoing fighting in several other cities across the country, including the central city of Homs, which on Wednesday saw fierce clashes between rebels and regime forces and was bombarded by mortars, artillery and rockets, according to the activist group Syrian Observatory for Human Rights.
In Aleppo, the state news agency reported several victories by government forces, especially in the hotly contested rebel bastion of Salaheddine, saying dozens of "terrorists" had been killed, including some with "African" nationalities.
For their part, however, rebels said they had extended their control over the strategic city by taking two police stations in Saliheen and Bab al-Neyrab neighborhood in the battles that lasted several hours.
Turkey, meanwhile, launched a military drill just across the border from a Syrian town it claims is controlled by Kurdish rebels -- a show of muscle aimed at Kurdish separatists pushing for autonomy within Turkey's borders.
The Turkish government last week said Turkish Kurdish rebels have seized control of five towns along the border in collaboration with their Syrian counterparts. Turkey alleges that the Kurdish guerrillas they are fighting have taken advantage of the strife in Syria to take refuge there.
The idea that Syria, like northern Iraq, could become a safe haven for Turkish Kurdish rebels is an anathema to Turkey's leaders, who otherwise have been very supportive to the rebels fighting Assad.
Associated Press writer Albert Aji in Damascus, Syria and Selcan Hajaoglu in Ankara, Turkey contributed to this report.