The cease-fire in Syria is holding, but NATO is concerned about Russia's military build-up in the country, NATO's secretary-general Jens Stoltenberg said, the Reuters news agency reported Monday.
"We are concerned about the significant Russian military build-up we have seen in Syria with the ground troops, with the naval forces in eastern Mediterranean and with air forces conducting air strikes," Stoltenberg said.
The cease-fire in Syria began on Feb. 27.
"This agreement and the full implementation of the agreement is the best possible basis for renewing the efforts to find a political negotiated peaceful solution to the crisis in Syria," Stoltenberg said.
Announced by the Kremlin and the U.S., the truce aims at ending the fighting between Syrian President Bashar Assad's forces and his political opponents. The agreement excludes the Islamic State, Nusra Front, and other groups designated as terrorist groups by the United Nations.
The Islamic State is a terrorist organization banned in Russia.