Russian President Vladimir Putin listens to Russian Foreign Minister Sergei Lavrov at a meeting of the Collective Security Treaty Organization in Dushanbe, Tajikistan, on Sept. 15, 2015. (Mikhail Klimentyev/Kremlin Pool Photo via AP)

President Vladimir Putin on Tuesday defended Russia’s military support for Syria, saying it was necessary to defeat the Islamic State and “terrorist aggression.”

Speaking at a meeting of a regional security bloc led by Russia, Putin rejected Western criticism that his support of President Bashar al-Assad has prolonged Syria’s bloody war, and he implied that the West’s backing for Syrian rebels has led to Europe’s refugee crisis.

“We support the government of Syria in its opposition to terrorist aggression,” Putin said in Dushanbe, the capital of Tajikistan, according to a transcript of his remarks. “We have provided and will provide necessary military and technical support and call on other nations to join us.”

Russia has been vocal in its political support for the Syrian government since the beginning of the conflict but has been reticent about its provision of military aid. A Russian Foreign Ministry spokeswoman confirmed last Wednesday for the first time that Russian military advisers were present in Syria, saying that their mission was to train Syrian troops to use arms and military equipment imported from Russia.

Russian President Vladimir Putin meets with Tajik President Emomali Rahmon before a summit of the Collective Security Treaty Organization in Dushanbe, Tajikistan, on Sept. 15, 2015. (Mikhail Klimentyev/Ria Novosti/Kremlin Pool/European Pressphoto Agency)

Putin did not specify what weapons Russia has supplied to Assad, but sightings of Russian armor and a small number of Russian troops have been reported this month in the Syrian port city of Latakia, an Assad stronghold. A Pentagon spokesman told reporters Monday that Russia appeared to be establishing a “forward operating base” near Latakia.

“Russia’s support for Assad has lengthened the war,” said Badr Jamous, a leader of the Syrian Opposition Coalition, noting Russia’s political protection of Syria during peace talks in Geneva. “It gave the message to Assad that he does not have to agree to peace.”

Putin on Tuesday also addressed Europe’s growing refugee crisis, saying the provision of arms to “radicals” by foreign powers had led to an exodus of Syrian civilians, many going to Europe.

“If Russia had not supported Syria, then the situation in the country would be even worse than in Libya, and the stream of refugees would be even greater,” Putin said.

The war in Syria has killed more than 250,000 people since 2011, according to U.N. statistics, and more than 4 million Syrians out of a population of about 22 million have fled the country. While Putin has focused on the role of the Islamic State militant group, other analysts and monitoring groups say Assad’s government is responsible for most of the deaths.

Putin called on the West to respect national sovereignty and reject military intervention. He also said that Assad may be willing to enter a power-sharing agreement with the opposition but that the fight against terrorism was the priority.

“We must sideline geopolitical ambitions, refrain from so-called double standards, from the policy of direct or indirect use of separate terrorist groups to achieve opportunistic goals, including the change of governments and regimes that may be disagreeable to whomever,” he said.

Putin did not address the conflict in Ukraine, which has left more than 6,500 people dead. Critics have accused his government of supplying arms and soldiers to prop up two self-proclaimed separatist states in eastern Ukraine. The conflict there, after a pro-European revolution in Ukraine’s capital, and Russia’s annexation of the Crimean Peninsula, have driven relations between Russia and the West to their lowest point since the Cold War.

During a relative lull in the fighting in Ukraine, the focus has returned to the role of Russia in the Middle East, particularly Russia’s support of Assad, and its part in securing a nuclear deal with Iran in July.

Putin is to address the U.N. General Assembly this month, for the first time in more than a decade. Foreign Minister Sergei Lavrov said this week that Putin would discuss the West’s use of sanctions as a “big stick” to “punish those who don’t cooperate.”

In Dushanbe, the Collective Security Treaty Organization, the security bloc that Putin addressed Tuesday, approved a joint statement against the use of sanctions “bypassing the U.N. Security Council.”

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Today’s coverage from Post correspondents around the world