The US government has verified reports that Syria's ambassadors to both Cyprus and the UAE have abandoned the Assad regime and fled to Qatar.

White House spokesperson Jay Carney confirmed the defections of Lamia Hariri and Abdel Latif al Dabbagh, Syria's emissaries in Nicosia and Abu Dhabi respectively.

The news follows the earlier defections of Syria's ambassador in Iraq, who has also decamped to Qatar, as well as two top army generals, who fled across the Turkish border.

Given that Hariri is a close relative of Syria's Vice President Farouk al-Sharaa, her desertion will be seen as particularly significant by anti-Assad activists.

Carney told reporters that the wave of defections is attributable to "the heinous actions taken by Assad against his own people, and the recognition that Assad's days are numbered."

As the defections mount, pro-government troops continue to fight against the rebels for control of Syria's second city, Aleppo. Fierce battles have been reported across the city, which is seen as strategically vital by both pro and anti-regime forces.

Reports suggest that pro-Assad troops continue to attack the rebels with artillery and helicopter gunships, causing significant damage to Aleppo. Most of the residents have already fled in search of sanctuary elsewhere.

Nearly 87 people, the majority of them civilians, died in fighting across the country on 25 July, following more than 150 fatalities the day before.