Mashudur Choudhury, who was convicted Tuesday, was one of at least five men from Portsmouth in southeastern England who traveled to Syria in October to fight alongside al-Qaida-linked militants seeking to overthrow President Bashar Assad.

Authorities hope Choudhury’s conviction will act as a deterrent to European militants contemplating a trip to the battlefield in Syria.

Last month the EU's anti-terrorism chief estimated that 500 Europeans had joined the Syrian rebels. Other estimates have put the number much higher. In December, the International Center for the Study of Radicalization estimated that as many as 1,937 foreign fighters from Western Europe alone had traveled to Syria.

Prosecutors said Choudhury sought firearms training and expressed a desire to become a "martyr.” According to trial testimony, he left Britain Oct. 8, travelling alongside four other Portsmouth area-men on a flight to Turkey before entering Syria.

Jurors heard that before departing Britain, Choudhury had been in regular contact via Skype and text with another jihadist named Ifthekar Jaman, who admitted fighting in Syria.

British authorities say that while Choudhury’s precise activities inside Syria are unknown, he sent out texts and messages on social media emphasizing that he was traveling there to participate in jihad. Prosecutors said Choudhury asked Jaman about purchasing a handgun and undergoing weapons training. Jaman, who reportedly was killed in December while fighting in Syria, told him his training would last between one and six weeks.

Choudhury was arrested at Gatwick Airport, 30 miles south of London, in March as he re-entered the country. He is scheduled to be sentenced June 13.

British officials touted his conviction as evidence that their counterterrorism strategy – which focuses on persuading friends, relatives and co-workers to contact authorities if they suspect that someone plans to join the jihad in Syria – is working.

"Today's conviction sends out strong message to anyone considering engaging in terrorist activity, be that in the UK or overseas, that we will pursue you and your networks," said  assistant chief constable Brendan O’Dowda, head of a regional police counterterrorism unit.

“Anyone thinking of traveling to fight jihad against the Assad regime, think again,” he warned. “You are likely to be killed or kidnapped,  and if you return to the U.K. you are highly likely to be arrested.”

• MI5: Syria Jihadists Pose Mounting Security Threat to Britain
  
• Jihadists Returning From Syria Create Headache For US Policymakers