Syrian government troops and moderate opposition groups supported by Russian soldiers have liberated three southern Syrian provinces from terrorists, the Russia's military said Thursday.

"As a result of the operation in southwestern Syria, 3,332 square km of territory with 146 settlements were freed," Sergei Rudskoi, chief of the Russian General Staff's Main Operational Directorate, said at a press briefing.

The liberated provinces of Daraa, As-Suwayda and Quneitra near the borders with Jordan and Israel include the southern de-escalation zone.

As agreed by Russia, the United States and Jordan, the de-escalation zone was set up last year to stabilize the situation in the region and allow for the delivery of humanitarian aid.

Before the start of the operation, the Islamic State and the Nusra Front terrorist groups controlled more than 55 percent of the southern de-escalation zone, Rudskoi said.

Terrorists there constantly engaged in military operations to seize Syrian government troops-controlled territory, which also endangered Russian military police guarding posts along the demarcation line, he said.

The Russian official said the United States and Jordan did not react to Russian reports on the worsening situation in and around the de-escalation zone, while local authorities asked the Russians to protect them from the terrorists.

At the same time, some moderate opposition groups in the region expressed the desire to voluntarily lay down their arms and return to peace under the guarantees of Russia, Rudskoi said.

As a result of the operation, the Syrian government troops fully restored control over the border with Jordan, he said.

The victory also allowed United Nations peacekeeping forces to resume their activities on the Syrian border with Israel in the Golan Heights for the first time since 2012, when their activities were suspended for security reasons, he said.