ANKARA (Reuters) - A Turkish court on Wednesday sentenced a lawmaker from the opposition Republican People’s Party (CHP) to 25 years in prison on spying charges, a move his party saw as an attempt to intimidate.

Enis Berberoglu, the first CHP lawmaker to be handed prison time since the lifting of parliamentary immunities last year, was accused of giving an opposition newspaper video purporting to show Turkey’s intelligence agency trucking weapons into Syria.

CHP leader Kemal Kilicdaroglu said he would launch a march in protest against the conviction at an Ankara park on Thursday. Party officials said the march would head to Istanbul.

“We are in the days where the actual guilty are not tried, but the innocent are,” he told reporters. “I will be in Guvenpark at 11 am (4.00 a.m. ET) tomorrow and we will begin our march until democracy and justice come to this country.”

A report in the secular Cumhuriyet newspaper in May 2015 said that trucks allegedly owned by Turkey’s state intelligence service were found to contain weapons and ammunition that were headed for Syria when they were stopped and searched in southern Turkey in early 2014.

“The defendant has committed the crime of disclosing information that should remain secret for state security, domestic and external benefits, with the aim of political and military espionage,” the court document seen by Reuters said.

The government has denied accusations that weapons were sent to Syria, saying the trucks were carrying humanitarian aid.

Slideshow ( 2 images )

Engin Altay, a deputy chairman for the CHP, said the decision was aimed at intimidating the opposition and was a sign that the judiciary was under government control.

“This decision is intimidation of the opposition. This decision is intimidation of all who are displeased with the AKP,” Altay told reporters outside the Istanbul court house, referring to President Tayyip Erdogan’s ruling party.

Following Cumhuriyet’s report, Erdogan acknowledged the trucks belonged to the National Intelligence Organization (MIT), and said they were carrying aid to Turkmens battling Syrian President Bashar al-Assad and Islamic State.

He accused Cumhuriyet journalists, including editor-in-chief Can Dundar and Ankara bureau chief Erdem Gul, of undermining Turkey’s reputation and vowed Dundar would “pay a heavy price”.

Last year, Dundar and Gul were sentenced to at least five years in jail for revealing state secrets in a related case, and the prosecutor is now seeking an additional 10 years in prison for the two over the report on the trucks.

Hurriyet Daily News editor Murat Yetkin noted Wednesday’s ruling came as Turkey already faced pressure because of the jailing of journalists and politicians.

“Rulings like this are likely to weaken the position of President Recep Tayyip Erdoğan and the AK Party government in their diplomatic ventures, especially with the West,” he wrote.

Rights groups and Turkey’s Western allies have complained of deteriorating human rights under Erdogan, and a crackdown following last July’s failed coup has seen 50,000 people jailed pending trial and some 150,000 detained or dismissed.