Yemen's capital Sanaa rocked by explosions

North of Yemen's capital Sanaa has been rocked by explosions and shelling, leaving at least 13 dead.

Reports said forces loyal to President Ali Abdullah Saleh clashed with armed men opposed to his rule. The violence came as Mr Saleh returned from Saudi Arabia three months after surviving an assassination attempt. His office called for a ceasefire to stop violence which has claimed about 100 lives already this week, mainly of unarmed anti-government protesters.

At least 40 people were injured in the clashes in the capital's Hasaba district on Friday. President Saleh, who has been in power for more than 30 years, has faced months of protests urging him to quit. Activists have been camped out in another area of Sanaa, dubbed Change Square, since January, demanding an end to President Saleh's rule.

There are fears that if the violence continues, the country could slip into civil war. 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.