SANA'A Radio warned yesterday that the forces of the northern Yemen leader, President Ali Abdullah Saleh, will continue to bomb the southern city of Aden, and advised civilians to stay away from strategic targets.

A southern military statement said northern Yemeni forces ringing the port city bombarded its northern districts at random yesterday. At least four people were killed in the barrage of shells and Katyusha rockets, hospital sources said.

Officials said at least 54 people had died in a bombardment on Thursday, though the Kuwait news agency put the death toll at 18, with 40 wounded. The northern warning was issued despite a pledge from Mr Saleh to agree to a new ceasefire in Yemen's six-week civil war. In Aden, the southern leadership yesterday urged the United Nations Security Council to brand Mr Saleh and his government 'war criminals'.

Southern radio quoted the south's foreign minister, Abdullah Abdel al-Majid al-Asnaj, as saying the north had embarked on a 'dangerous military escalation' and was 'attacking cities and residential districts'.

About 900 foreign evacuees - including Americans, Britons, Tunisians and Palestinians - arrived safely in Djibouti yesterday aboard a ferry after sailing overnight across the Gulf of Aden.

The country plunged into civil war after the four-year union of North and South Yemen collapsed amid a bitter feud between Mr Saleh and his former vice-president, Ali Salim al-Beidh, the southern leader. In recent days, the Sana'a government has stepped up secret contacts with the Saudi government to discover what Riyadh - which backs the south - would expect from any peace deal.

Mr Saleh has proposed a deal under which the Saudis would recognise that Yemen is a single, united state and Yemen would offer a swift agreement on the borders between the two countries.

At the UN, the Saudis have begun lobbying for another Security Council resolution on the conflict. The Saudis have offered to pay the cost of sending UN observers to the war zone.

Back in Aden the people can only wait. They are without water, electricity or sewage. Young men are picked up off the street and sent to the front. A few days ago, about 100 of them were dumped in a minefield.