Escalating tensions with Russia, Turkey defended its forced landing of a Syrian passenger jet en route from Moscow to Damascus, saying Thursday it was carrying Russian ammunition and military equipment destined for the Syrian Defence Ministry.

Syria branded the incident piracy and Russia called the search illegal, saying it endangered the lives of Russian citizens aboard the plane.

The accusation by Turkish Prime Minister Recep Tayyip Erdogan contradicted denials by both Russia and Syria that anything illegal had been aboard the Airbus A320 that was intercepted over Turkish airspace late Wednesday.

"Equipment and ammunitions that were being sent from a Russian agency ... to the Syrian Defence Ministry," were confiscated from the jetliner, Erdogan told reporters in Ankara. "Their examination is continuing and the necessary (action) will follow."

Reports of missile parts

He did not provide details, but Turkish media said the seized cargo included missile parts as well as radio receivers, antennas and other military communications equipment.

"As you know, defence industry equipment or weapons, ammunitions ... cannot be carried on passenger planes," Erdogan said. "It is against international rules for such things to pass through our air space."

Erdogan refused to say how — or from whom — Turkey had learned that the twice-weekly scheduled flight would be used to transport military gear to Syria.

"As you will appreciate, those who gave the tip, which establishments, these things cannot be disclosed," he said.

U.S. and Canada back Turkey

The United States said it backed Turkey's decision to intercept the plane.

"Any transfer of any military equipment to the Syrian regime at this time is very concerning, and we look forward to hearing more from the Turkish side when they get to the bottom of what they found," said State Department spokeswoman Victoria Nuland.

She declined to comment on Turkish reports that the intelligence on the plane's contents had come from the United States. The plane was allowed to continue to Damascus after several hours, without the cargo.

The action by Turkey also won the wholehearted approval of Canada's foreign affairs minister, John Baird.

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Turkey's Prime Minister Recep Tayyip Erdogan said the contents of the plane were being examined and that the "necessary" action would be taken. (Associated Press)

In a statement, Baird said that Canada has continually supported efforts to prevent weapons from reaching Syrian President Bashar al-Assad's regime, amid what he described as the leader's "bloody struggle to cling to power."

"We commend Turkey on successfully stopping one such shipment today," Baird said. "These efforts will help limit the Assad regime's ability to kill civilians in Syria."

Baird added that Canada wants the bloodshed in Syria to end quickly, and urged the UN Security Council to push for further sanctions as well as an arms embargo "to bring pressure to bear on the Assad regime."

Turkish-Syrian relations have plummeted over the conflict in Syria, which has expanded into a civil war that threatens the stability of the Middle East. Syrian opposition activists estimate more than 32,000 people have been killed since March 2011, when the uprising against President Bashar al-Assad's regime began.

17 Russian citizens on board

Turkey has called for Assad to step down and Damascus accuses Turkey of supporting the rebels. The two neighbours have traded artillery fire over Syria's northern border throughout the past week.

Hours before, the Turkish statement Russian Ambassador Vladimir Ivanovsky had held talks with Turkish officials at the Foreign Ministry.

Russian Foreign Ministry spokesman Alexander Lukashevich had said earlier Thursday that Moscow was concerned that lives and safety of the 35 passengers, including 17 Russian citizens, had been endangered.

He said Turkey without explanation denied Russian consular officials and a doctor access to the passengers, who had not been allowed into the airport for eight hours or provided with food.

"The Russian side continues to insist on an explanation for the Turkish authorities' actions toward Russian citizens and on the adoption of measures to avoid such incidents in the future," Lukashevich said in a statement.

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Syria has denied that the plane, which was intercepted by Turkish military jets on Wednesday, was carrying illicit cargo. (Burhan Ozbilici/Associated Press)

Turkey's Foreign Ministry issued a statement saying that the pilot of the Syrian Air plane from Moscow had been warned of Turkey's intention to ground it as he approached from the Black Sea on Wednesday evening. It said he was given the chance to turn back, but that he decided to continue his course.

Rejecting claims that passengers were ill-treated, the Turkish statement said they were allowed to leave the plane if they wanted and that there was a medical crew and ambulances on standby. It also said that the pilot did not provide a passenger list and therefore Turkish officials did not know there were Russians on board until after it landed.

Separately, the Foreign Ministry said it had submitted a formal protest note to Syria for the violation of civil aviation rules and declared Syrian air space unsafe for Turkish planes.

Syrian Transportation Minister Mohammad Ibrahim Said said Turkey's decision to force the plane to land amounted to piracy.

The general manager of the Syrian Civil Aviation Agency also blasted Turkey's forced landing of the plane, calling it "contrary to regulations and aviation norms."

Ghaidaa Abdul-Latif told reporters in Damascus that the plane's pilots were not asked to land but were instead surprised by Turkish F-16 fighter jets, which forced them to land.

Moscow airport denies 'forbidden' cargo on board

A Syrian Airlines engineer who was aboard, Haithan Kasser, said armed Turkish officials boarded the plane and handcuffed the crew before inspecting packages that he said contained electrical equipment.

Abdul-Latif said the officials seized some packages after presenting official documents.

The Moscow airport that cleared the Syrian plane for takeoff denied there was any forbidden cargo on board.

"No objects whose transportation would have been forbidden under aviation regulations were on board," said Vnukovo Airport spokeswoman Yelena Krylova, ITAR-Tass reported

Krylova said all documentation related to the cargo was in order. She would not say who had sent the cargo.

A Syrian Foreign Ministry spokesman also denied that the plane carried any arms or prohibited goods and called on Turkey to return the plane's full contents.

Inside Syria, battles continued in the southern Idlib province that abuts the Turkish border as rebels sought to consolidate control of a strategic town on the country's main north-south highway. Rebels said they captured Maaret al-Numan on Wednesday. The Britain-based Syrian Observatory for Human Rights said clashes continued Thursday after rebels attacked a military convoy and nearby army checkpoints. The fighting killed more than a dozen people, the Observatory said.

The Observatory also said eight people were killed and another eight wounded when unknown gunmen fired on their bus near the coastal city of Tartous. Syria's state news agency SANA said the men were Syrian workers returning from Lebanon.

In the southern province of Daraa, gunmen shot dead the brother of a member of Syria's parliament while raiding his home, the Observatory and SANA said. The parliament member, Khalid al-Abboud, regularly defends the Syrian regime on TV.

The Observatory said gunmen also killed the son of another legislator, Mohammed Kheir al-Mashi, at his home in Idlib province.

Activist claims could not be independently verified because of restrictions on reporting in Syria.

State-run Syrian TV said there was an explosion in the capital Thursday night at the Ministry of Education and the Military Court. A Syrian official said the blast wounded two people and caused material damage. The official asked that his name not be used because he is not allowed to speak publicly.

With files from CBC News