Syrian President Bashar al-Assad is visiting the city of Aleppo to take a first-hand look at the fighting between government forces and rebels and has ordered 30,000 more troops into the battle, a Lebanese paper said on Tuesday.

Al-Diyar newspaper, which is known for its pro-Assad stance, said the president had flown by helicopter at dawn from the presidential palace in Damascus to Aleppo.

It did not specify what day the trip started but said that Assad was still in Aleppo. The visit was decided on after reports that the situation in the city, Syria's largest and its commercial center, had become very serious.

"President Assad ordered units 5 and 6, estimated to be 30,000 soldiers and 2,000 personnel carriers, to move from Hama to Aleppo and to attack any occupied areas of Aleppo province from the Turkish border," it said.

Reuters was unable to independently verify the report. An employee of al-Diyar told Reuters it had a correspondent in the city. Syrian state media made no mention of any visit.

Rebels mounted a new offensive last week to seize the city, which was until July firmly under Assad's control. They claim to hold most of the Old City but are struggling to hang on to their positions in the face of heavy artillery fire.

The rebel forces are in the east and Assad's forces in the west of Aleppo. Fires started by the combat have gutted the historic market in the Old City, a world heritage site.

Opposition activists say 30,000 people have been killed in the 18-month-old anti-Assad uprising, which has grown into a full-scale civil war.

For much of the revolt, Assad retained a grip on Aleppo. Many rich merchants and minority groups, fearful of instability, chose to stay neutral while pro-democracy protests spread.

Syrian authorities have painted the uprising as a foreign-backed "terrorist" conspiracy.

The paper said that Assad gave orders that Aleppo must be "cleansed" during the visit. – Reuters