text: At least 35 workers have been killed at a dairy factory in Yemen as Saudi Arabian warplanes continue to bomb Shiite rebel positions in both the north and the south of the country. Today's airstrikes targeted rebel-controlled army camps in the Red Sea port city of Hodeida, and hit warehouses belonging to a factory that produces dairy products. The jets drew return fire from anti-aircraft guns as the Saudi-led campaign to defeat the Iran-backed Shiite rebels loyal to Yemen's deposed president Ali Abdullah Saleh entered its seventh day. The attack on the dairy factory comes as Saudi Arabia hinted that it was prepared to launch a ground invasion in Yemen in the hope of forcing the Houthi rebels to allow current president, Abed Rabbo Mansour Hadi to return to the country, after he fled the southern port city of Aden last week. Hit: Smoke rises from the dairy factory hit by an air strike in Yemen's western port city of Houdieda today . Blast: Today's airstrikes targeted rebel-controlled army camps in the Red Sea port city of Hodeida, and hit warehouses belonging to a factory that produces dairy products . Under attack: Houthi fighters walk as smoke rises from a military supply post after it was hit by an air strike in Yemen's northwestern city of Saada earlier today . Yemeni supporters of the Saudi-led coalition hold pictures of Saudi King Salman bin Abdulaziz al-Saud alongside Saudi and Yemeni flags during a demonstration against the Shiite Houthi rebels in Taez city today . Since their advance began last year, the Houthis have overrun the Yemeni capital, Sanaa, and several provinces, and have forced current president Abed Rabbo Mansour Hadi to flee abroad. Following today's airstrikes on the dairy factory in Hodeida, the Houthi's anti-aircraft guns returned fire before the factory itself was set ablaze. Parts of its main building collapsed from explosions with workers still inside, according to at least five eyewitnesses and officials. According to the medical center in Hodeida, at least 35 workers were killed, many of them crushed by the rubble or burned to death. Two military officials said the factory had been used as a rebel weapons cache, and that while the airstrikes flattened the warehouses, the main factory building was only partially destroyed - suggesting it might have been hit from ground. All the officials and witnesses spoke on condition of anonymity because they were not authorized to speak to the media. Families of stranded Pakistanis in Yemen hold their pictures in a rally for their rescue in Multan today . Yemeni men chant slogans while holding posters of  the Shiite Houthi rebel leaders they support . The airstrikes come as Saudi Arabia hinted once again that it could carry an ground invasion in Yemen in the coming days. Authorities  reiterated that the Sunni alliance, which was set up by the Arab nations against the Houthi Shiite rebels, is boosting its military presence in the Saudi Arabia-Yemen border. Saudi Arabia shares a 1,120 mile-long border with Yemen -- much of which is incredibly porous. 'The Saudi-led air campaign may be accompanied by an operation on the ground,' Saudi Arabia's Brigadier General Ahmed Asseri was quoted as saying by the International Business Times. 'One should not expect a sudden ground attack,' he reportedly added. 'The Houthis are moving from one place to another in search of safe havens. We will make sure that there will be no safe place the militants to hide on the land of Yemen,' General Asseri went on to say. Scores of Yemeni expatriates, including students and clerics, chant slogans while holding a poster of the Yemeni Shiite Houthi rebel leader Abdul-Malik al-Houthi, during a protest  in Tehran, Iran this morning . Yemeni men in Tehran hold a burning photo of Saudi King Salman, with Arabic writing reading 'Horn of Satan' The Hodeida death toll came a day after international aid groups expressed alarm over high civilian casualties in Yemen's escalating crisis. A report published yesterday by the U.N. children's agency, UNICEF, said 62 children were killed and 30 wounded during the fighting in Yemen over the past week. It was not clear if the deaths were the result of airstrikes or ongoing clashes between rival groups across the country. The U.N. human rights office in Geneva also said its staffers in Yemen confirmed that at least 19 civilians died when airstrikes hit a refugee camp near the Houthi stronghold of Saada in northern Yemen on Sunday, with at least 35 wounded, including 11 children. Critics of the Houthis charge that they are an Iranian proxy — a claim the rebels deny. Iran has provided aid to the rebels, but both Tehran and the Houthis deny it has armed them. In Tehran, dozens of Yemeni expatriates, including clerics and students, took to the streets on Wednesday to denounce the airstrikes. The protesters burned photos of Saudi King Salman and marched outside the Saudi Embassy.
target: Dairy factory in Red Sea port city of Hodeida was destroyed earlier today .
  35 people were killed in airstrike that prompted Houthi rebels to return fire .
  Attack comes as Saudi issues new warning of imminent ground invasion .
  General hinted that ongoing airstrikes may require support on the ground .