But southern Yemen said a northern army brigade - 2,000 to 3,000 men - trying to break through to Aden had been smashed, that defeated north Yemeni troops were 'running like scared cats' and had not got closer than 60 kilometres (40 miles) from the city. Independent witnesses reported attacks visible from Aden, indicating that northern Yemeni forces had got closer than the south was prepared to admit.
Independent military sources believe that the northern forces, though numerically stronger, have not reached Aden and could be bogged down outside it for some time. They are only supplied down one main road - the north-south road - and could have problems with food, ammunition and, above all, water. It is likely that the forces will consolidate on the lines of the old north-south divide.
Aden - the capital of southern Yemen before unification of the two states on 22 May 1990 - is the obvious target for the northern forces but would be difficult to hold if captured. The rest of southern Yemen, far larger but more sparsely populated than the north, could resist indefinitely.
Since unification, naval forces have been concentrated at Aden, and in addition to Aden's role as a political, economic and communications centre, such naval forces could well be a northern objective.
The northern brigade is the Amaliqa - 'Giants', an elite formation stationed at Zingibar, 60 km north-east of Aden. Southern sources say Zingibar was the closest the northerners had come to Aden. The presence of the Amaliqa brigade close to Aden at the outbreak of fighting would give the north the opportunity to claim a successful 'penetration' of southern positions, whereas it might simply be trapped. Neither side's claims could be verified yesterday.
The southern command announced on Sunday that Zingibar had been recaptured from the Amaliqa brigade in heavy fighting. The south has consistently denied claims by northern commanders that their troops were only 20 km from Aden.
The southern statement said that after a three-day battle, southern forces had also repulsed three northern brigades advancing on the mountain town of Dhala close to the former border with north Yemen, and regained control of the main road linking Dahlea to Aden.
Southern forces in Lahij, where the main road from north Yemen runs down a strategic valley to Aden, had destroyed the northern Second Armoured Brigade and captured many of its troops and some of its tanks, according to the statement broadcast on radio and intercepted in Djibouti.
Before unification north Yemen had a population of 9.2 million in a territory of 195,000 square kilometres, and armed forces of 38,500 including perhaps 25,000 conscripts. The south had 2.3 million in 336,000 square kilometres and 27,500 under arms, including 18,000 conscripts.
The sides are fairly evenly matched in hardware: before unification the north had 87 combat aircraft, the south 94 and 12 armed helicopters.
The north could field 12 SS-21 short-range missile launchers - a recent and highly accurate system from Russia with a range of up to 100 km; the south 12 Frog-7 launchers (range 70 km) and six Scuds, of Gulf war fame, range up to 300 km. The number of missiles is unknown. A number of Scuds have been fired at the northern capital, Sanaa. After unification, there was little amalgamation of the armed forces - a factor which facilitated the present conflict.
North of Aden lie the Amman mountains, a significant barrier to forces advancing southwards which can be trapped in narrow valleys. If the reports of northern forces close to Aden are true, they may already have passed this barrier, although those reports may only refer to the Amaliqa brigade, which was already on the coast east of Aden when fighting erupted last Wednesday.
In terms of classical military strategy, it is better to oppose an enemy when he is across the mountain barrier, as he is at the end of tenuous communications.
Before unification, clashes followed a familiar pattern. Border incidents would lead to more generalised fighting. Southern forces, generally better disciplined with officers trained by Britain and then the Soviet Union, would advance. Northern forces would retreat in disarray until the tribal levies would rally and save the day.
One explanation for the eruption of fighting last week is that President Saleh instigated a putsch to remove his southern rival, Vice President Ali Salem al-Beidh from power. It was not the President's wish to get embroiled in full-scale civil war which could lead to the break-up of the union. It was an act of political brinkmanship with a high risk of failure, given the success with which the south now appears to be counterattacking.
Ever since the southerners forged a union with the north, on the anvil of common interest, the southerners have resented being treated as unequal partners. The southern leader, whose Marxist world-view had long been tempered by pragmatism, saw union as a way out of the south's ideological and economic bankruptcy. By the mid-1980s, south Yemen's isolation and pro- Soviet stance had brought few benefits. And it was desperately poor.
The south brought little to the union, but almost immediately came into a small fortune. Almost all the oil and gas discovered since unification have been in the south. Production is now nearly 130,000 barrels a day, half the total for Yemen as a whole. And the south feels oil revenues should be spent on its own development rather than the whole country.
The fighting has sent shockwaves throughout the region. The Saudis always opposed the unification of the two Yemens. Despite Mr al- Beidh's Marxist past, the Saudis preferred him to the northerners, whom they hold responsible for Yemen's support of Saddam Hussein during the Gulf war. Above all, the Saudis fear the potential for regional destabilisation if the fighting intensifies.
(Map omitted)Reuse content