Tension continues to build after an Israeli airstrike in Syrian territory. The attack which occurred earlier this week prompted Syria to deliver a letter to the United Nations declaring its right to defend itself. The letter, sent on Thursday, prompted several nations to condemn Israel’s actions, including Iran and Russia.

Israeli officials continued to remain silent about Wednesday’s airstrike, which American officials say hit a convoy carrying SA-17 antiaircraft missiles to Lebanon. Syria and its allies say the target was actually a research facility near Damascus, where some analysts suspect chemical weapons may have been in production.

Though Syria has cried foul over the attack, it remains unclear if they will directly retaliate. The Syrian military is still fighting a 22-month uprising in that nation, and some believe the military is moving weapons to Lebanon with aid from Hezbollah in order to keep them out of rebel hands.