Yemen unrest: 'At least 17 dead' in Sanaa attack

At least 17 people have been killed in a government assault on protesters in the Yemeni capital Sanaa, the BBC News reported.

Witnesses say the demonstrators came under attack in the capital's Change Square - the focus of months of protests.

The attack on the camp's southern end reportedly started late on Friday.

The violence comes a day after the return of President Ali Abdullah Saleh from three months' treatment in Saudi Arabia following an assassination bid.

Correspondents say his arrival back in Yemen raises the risk of all-out civil war.

The upsurge in violence happened at the end of a week of fighting in which scores of people are reported to have died.

Mohammed al-Qabati, a medic at the field hospital in the square, told AFP news agency 55 were wounded in the latest attack.

A number of soldiers from a defecting military brigade which has been protecting protesters were among those killed, Qatabi and a spokesman for the brigade said.

Tents and buildings were set on fire, witnesses said.

A resident near the camp told Reuters news agency that government forces had used armoured vehicles and rifles.

"It was an intense fight... My house was shaking like crazy... There are no protesters there now - it's just armed people," the witness said.

Other reports spoke of government troops shelling the 4km (2.5-mile) stretch of avenue which protesters have dubbed Change Square.

Earlier on Friday, at least 13 people reportedly died in fighting in the capital.

Activists have been camped out in Change Square since January, demanding an end to Mr Saleh's decades-long rule.

Clashes in the capital have recently intensified as elite Republican Guards, led by President Saleh's son Ahmed, fight running battles with army units that have defected to the opposition and tribal fighters who support the protesters.