DAMASCUS, Syria – Syria accused neighboring Turkey Sunday of allowing thousands of Muslim extremists to cross into its territory, as the government and opposition said an explosion killed at least seven and cut off a main road leading south from the capital.

In letters to the U.N. Security Council and Secretary-General Ban Ki-Moon, Syria's Foreign Ministry said Turkey allowed "thousands of al-Qaida, Takfiri and Wahhabi terrorists" access to the country in order to "kill innocent Syrians, blow up their properties and spread chaos and destruction."

Syrian authorities blame the anti-government uprising that began in March last year on a foreign conspiracy and accuse Gulf countries Saudi Arabia and Qatar, along with the U.S, other Western countries and Turkey, of offering funding and training to the rebels, whom they describe as "terrorists."