The United Arab Emirates (UAE) confirmed that it launched airstrikes on Yemen’s interim capital Aden, after the Saudi-led coalition backing the Yemeni government accused the Gulf state of killing scores of its troops in bombing raids.

The latest round of accusations between the UAE and Saudi Arabia risk straining an already complex conflict in war-torn Yemen. Yemen’s five-year-long war has become more complicated and multi-partied in contrast to the beginning of the war. In the first years, there were the Iranian-backed Shiite Houthi rebels who were challenging the authority of the internationally recognized government.

After the Saudi Arabia-led coalition got involved, more lives were claimed but any attempt at a lasting truce failed. Now, Yemen is now split along two fronts after years of conflict that has left tens of thousands of people dead and pushed the country to the brink of famine.

On one front, southern forces and the government, backed by a Saudi-led coalition, are both battling the Houthis who are aligned with Riyadh’s archfoe Iran. On the other, the so-called Security Belt Forces, dominated by the UAE backed-separatist Southern Transitional Council (STC), are fighting to regain the south’s independence. On Friday, three separatist fighters were killed in a suicide bombing in Aden, the first such attack since Yemeni government forces were expelled from the southern city on Aug. 10.