HAMAT, Lebanon (Reuters) - The United States delivered two A-29 Super Tucano light attack aircraft to Lebanon s army on Tuesday, a sign of continued U.S. support despite Israeli accusations that the Lebanese military is controlled by Hezbollah.  The planes will be used as armed observation aircraft, a security source in Lebanon said, and represent a big upgrade for the Lebanese Armed Forces (LAF).  Earlier this month, U.S. ally Israel said Hezbollah, an Iran-backed Shi ite Muslim movement, had gained control over Lebanon s conventional military, a charge the Lebanese army denies. Hezbollah, which was designated as a terrorist group by the U.S. State Department in 1997, last fought Israel in a war in 2006. Lebanon is formally in a state of war with Israel.    The significant increase in LAF combat capability that this aircraft represents will ensure that the LAF will remain a national unifying force, a bulwark against extremism and terrorism,  said U.S. Ambassador Elizabeth Richard. The Islamic State militant group held a pocket of land straddling Lebanon s border with Syria until August.  Over the last decade, the U.S. government has invested over $1.5 billion in training and equipment, and has trained over 32,000 Lebanese troops, Richard said.  We have recently announced another $120 million in foreign military financing, which brings the total investment in the LAF to over $160 million just this year,  she said. The United States will deliver another four Super Tucanos to Lebanon.  The two new aircraft - which have advanced combat and surveillance capabilities - will  make a qualitative leap in improving the aerial capabilities of the LAF,  said Lebanese Army Commander General Joseph Aoun. 