Flights are being directed to Aden, Yemen's business capital, after the fierce clashes between the forces and the loyalists to sheikh Sadiq Al-Ahmer expanded to Sana'a International Airport.

The clashes intensified earlier today, with the armed tribesmen taking over more government buildings.

Casualties were reported but there was no exact number of deaths.

Over the first and second days of the battles that raised fears civil war in the country has just started, tens were killed and hundreds injured from both sides.

Earlier today, President Saleh said the forces saboteurs and destructive elements who sought civil war.

In a news conference, he said that there is a civil war in Yemen but with the tribal loyalists to Al-Ahmer.

Eyewitnesses said that the battles were continuing with huge explosions heard in more sites near the main battlefield in Al-Hasaba area where the forces shelled the house and fought the guards of Al-Ahmer.

The UN has expressed concern about these developments in Yemen. Spokesmen for the UN Secretary General Martin Nesirky said in a statement that the UN is very concerned the clashes in the Yemeni capital will make the situation much worse.

Today, massive demonstrations were held in some provinces including the capital to affirm that the youth-led uprising in the squares of change and freedom is peaceful and had nothing to do with the battles between the government forces and the tribes.

They chanted slogans such as: 'our revolution is peaceful', ' no to war', and 'the people want to oust the regime'.

No incidents were reported as month-long street sit-ins continued in most of the Yemeni cities.