Gunmen Loyal to Ex-Leader Strike the Main Airport in Yemen SANA, Yemen (AP) - The obstacles facing Yemen's new president were highlighted Saturday as gunmen loyal to his predecessor attacked the country's main airport, forcing its closing, and a military commander who was fired on Friday was reported to be refusing to leave his post. Armed tribesmen and uniformed troops in pickup trucks mounted with heavy weapons opened fire on an airport tower here in the capital, Sana, an airport official said. Then they surrounded the airport and sent passengers" vehicles away. The attack came a day after the new president, Abdu Rabbu Mansour Hadi, fired key security officials appointed by Ali Abdullah Saleh, who stepped down as president in February following a yearlong uprising. Mr. Hadi has pledged to purge Saleh loyalists from the army, the security apparatus and key government positions. Among those fired on Friday were Mr. Saleh's half brother, the air force commander Mohammed Saleh al-Ahmar, and his nephew, Tariq Saleh, who headed the presidential guard. Earlier, Mr. Saleh's son, who remains in command of the powerful Republican Guards, appointed Tariq Saleh commander of one of the biggest brigades in the guards. The appointment was reported by state television though Mr. Hadi's aides said the president never approved him. Mr. Saleh received immunity from prosecution in a deal to leave office, but critics of the agreement say it gave him the ability to act as a leader behind the scenes and plot a comeback, possibly by sowing instability. On Thursday, Defense Minister Mohammed Nasser Ahmed told Parliament that Mr. Saleh was still giving orders to governors and security officials using his son's Republican Guards headquarters as his operation room. Mr. Saleh's opponents are particularly worried about his loyalists who command military units. The army has recently suffered several defeats in its war against militants linked to Al Qaeda who have taken control of several towns in the south of the country, and many believe that Saleh commanders may be actively sabotaging the campaign. The airport attack suggests that removing the commanders comes with its own set of dangers - if it is even possible.