AP, Sanaa :Saudi-led coalition warplanes pounded Yemen’s Shiite rebels for a sixth day on Tuesday, destroying missiles and weapons depots and for the first time using warships to bomb the rebel-held airport and eastern outskirts of the port city of Aden.The airstrikes’ campaign by Sunni Arab states, which began last week, is meant to halt the advance by the Shiite rebels known as the Houthis who have overrun the country and forced Yemen’s president to flee abroad.Overnight and into early hours Tuesday, the coalition bombed the Iran-backed rebels around the capital, Sanaa, according to Yemeni military officials. The strikes targeted Houthi positions and camps, as well as weapons depots controlled by the rebels, the officials said.Meanwhile, Iran said it sent an aid shipment to Yemen, according to the official IRNA news agency – Tehran’s first such delivery since the Saudi-led airstrikes started last Thursday. The aid contained 19 tons of medicines and medical equipment and two tons of food provided by the Iranian Red Crescent, IRNA said.The agency reported that the aid was delivered by air early Tuesday but did not say where the cargo landed. The coalition has bombed a number of rebel-held airports and has announced it is in full control of Yemen’s airspace.The conflict in Yemen marks a major escalation in the regional struggle for influence between Saudi Arabia and Iran, which also back rival sides in Syria’s civil war. Arab leaders unveiled plans at a conference Sunday in Egypt to form a joint military intervention force for Yemen, which could raise tensions further.