The Ramadan offensive began in February 1963 when Amer and Sadat arrived in San'a. Amer asked Cairo to double the 20,000 men in Yemen, and in early February the first 5,000 of the reinforcement arrived. On February 18 a task force of fifteen tanks, twenty armored cars, eighteen trucks and numerous jeeps took off from San'a' moving northwards, heading for Sadah. More garrison troops followed. A few days later another task force, spearheaded by 350 men in tanks and armored cars, struck out from Sadah southeastwards toward Marib. The maneuvered into the Rub al-Khali desert, perhaps well into Saudi territory, and there they were built up by an airlift. Then they headed westwards. On February 25 they occupied Marib and on March 7 they took Harib. A royalist force of 1,500 men ordered down from Najran failed to stop them on their way out from Sadah. The royalist commander at Harib fled to Beihan, on the British-protected side of the border. In the battle of El Argoup, southeast of San'a, 500 royalists under Prince Abdullah's command attacked an Egyptian position on top of a sheer-sided hill that was fortified with six Soviet T-54 tanks, a dozen armored cars and entrenched machine guns. The royalists advanced in a thin skirmish line and were plastered by artillery, mortars and strafing planes. They replied with rifles, one mortar with 20 rounds, and a bazooka with four rounds. The battle lasted a week and cost the Egyptians three tanks, seven armored cars and 160 dead. The Egyptians were now in positions from which they could hope to interdict the royalist movement of supplies in the mountains north and east of San'a'. In the beginning of April the royalists held a conference with Faisal in Riyadh. They decided to adopt new tactics, including attempts to get supplies around the positions now held by the Egyptians by using camels instead of trucks to cross the mountains to reach the positions east of San'a. Camel caravans from Beihan would swing into the Rub al-Khali and enter Yemen north of Marib. It was also decided that the royalists must now strengthen their operations west of the mountains with three "armies". By the end of April, they began to recover and contended to have regained some of positions from the Egyptians had taken in the Jawf, particularly the small but strategic towns of Barat and Safra, both in the mountains between Sadah and the Jawf, and were able to move freely in the eastern Khabt desert.