Sanaa: Yemen clashes on Friday spilled across country’s capital as a powerful militia alliance warned embattled President Ali Abdullah Saleh to either step down or face civil war. At least 28 people were killed as the four-day death toll neared 110.

The bold ultimatum indicated the growing confidence among the opposition forces led the Yemen's largest tribe that they could be gaining the upper hand against Saleh's regime
with the uprising shifting from near daily street protests to fast-moving urban combat.

Saleh not to go easily

But Saleh also has shown he will not go easily. He has managed to ride out swelling anti-government demonstrations for more than three months, defections of military commanders
and pressure from Arab neighbours and Western powers to leave office.

The difference this time for Saleh could be the vast influence of Yemen's main tribes, which command well-armed militias and can tap into traditional clan-based loyalties to try to bring down Saleh's 32-year rule.