As Saudi-led airstrikes continue to hit targets in the capital of Yemen, Riyadh is boosting its fighting force.<br /><br /> The King of Saudi Arabia has ordered the Saudi National Guard to join the air force and army in the campaign against Houthi rebels allied with Iran.<br /><br /> At least 40 people are reported to have died in airstrikes on Tuesday, most of them civilians, according to health workers.<br /><br /> Dozens more have been wounded.<br /><br /> In key towns, fighters loyal to the exiled president Abd Rabbu Mansour Hadi are locked in battle with Houthi forces and other supporters of ex-president Ali Abdullah Saleh.<br /><br /> As Iran hints that a ceasefire may be on the cards, the US boosted its presence in the region, sending an aircraft carrier and a guided missile cruiser to waters near Yemen.
