Scores of mercenaries – including high - ranking commanders – fighting on behalf of Saudi Arabia against Yemen have been killed in retaliatory attacks by Yemeni forces in the country’s al - Jawf region, a report says. They were killed in operations carried out jointly by the Yemeni army and Popular Committees in al-Jawf’s al-Wadiyah region on Friday, Yemen’s al-Masirah television said in a news flash. Meanwhile, allied Yemeni forces have begun large-scale operations against Saudi Arabian military bases, including those in the southern Nijran region. The operations involve the use of heavy missile and artillery fire. The Yemeni Defense Ministry says at least 30 different positions and military bases held by Saudi Arabian forces have been completely cleared in the preliminary phase of the large-scale offensive. According to the Defense Ministry, large numbers of military vehicles have been destroyed in the operations. Yemen’s army spokesman Brigadier General Sharaf Luqman announced the launch of the offensive against Saudi Arabia on Thursday. He said the Saudi cities of Najran and Jizan had been surrounded by Yemeni forces, and that an attack on the cities – both located in Saudi Arabia’s southwest – was now awaiting a “political decision” to be launched. Yemen has been under constant military attacks by Saudi Arabia since late March. The Saudi military strikes were launched to supposedly undermine the popular Ansarullah movement, and bring fugitive former Yemeni President Abd Rabbuh Mansour Hadi, a Saudi ally, back to power. Members of Ansarullah have been in control of state matters approximately since Hadi resigned and fled Yemen earlier this year. More than 7,500 people have been killed and over 14,000 others wounded since March. Yemeni army soldiers and allied fighters from Popular Committees – who are loyal to the Ansarullah movement – have been conducting retaliatory attacks against Saudi Arabia.