ISTANBUL - There is a growing diplomatic dispute between Turkey and Denmark over the release of a Turkish man suspected of shooting a Danish writer and anti-Muslim activist. The man, who was released from police custody in September as part of an alleged exchange for 49 hostages held by the Islamic State, is now believed to have joined the radical group in Syria.

The suspect is 27-year-old Basil Hassan of Lebanese descent who is wanted in Denmark for the attempted assassination of Danish writer Lars Hedeggard, a well known critic of Islam.

According to Danish police, the suspect fled Denmark on the day of the attempted shooting and spent time in Syria before being arrested in Istanbul's Atatürk Airport while trying to enter Turkey using a fake passport in April.

In a statement, the Turkish foreign ministry said Hassan was released after proper judicial rules were applied.

Deep dispute

According to media reports, he since has crossed into neighboring Syria and joined Islamic State.

Diplomatic columnist Semih Idiz of the Turkish newspaper Taraf and Al Monitor website warned that Turkey and Denmark's dispute over the release was not expected to be quickly resolved.

"Obviously the Danes are very angry. We seen remarks and statements from the highest level. Even the president has commented, saying the matter is not closed," said Idiz.

The Danish government plans to cite Turkey's involvement in the case when the EU meets later this month (October 31) to analyze whether Turkey has been adhering to union membership standards.

Ankara also has an axe to grind with Copenhagen.

Last week, a Danish court cleared 10 Kurds who were accused of channeling almost $24 million to Turkey’s banned Kurdistan Workers’ Party (PKK), designated a terrorist organization by the European Union and the U.S.  The PKK also is fighting the Turkish state for greater Kurdish rights.

Columnist Idiz said the releases would only add to Ankara’s feeling of hypocrisy by the Danes over fighting terrorism.

"Ankara has for years, been demanding people from Denmark who it says are PKK terrorists. It has also been demanding that Denmark close down a TV channel that Turkey says is a mouthpiece for the PKK, an organization Turkey considers to be terrorists. So there is also a tit-for-tat element in all this," said Idiz.

Ankara's dealings

Denmark is not the only western country concerned with Turkey's release of a suspected radical Islamist.

Britain reportedly was angered over reports that two of its citizens were among nearly 200 militants held by Turkish authorities that were exchanged for 49 Turkish hostages held by the Islamic State.

These incidents are likely to fuel western concerns about Ankara’s stance in the battle against the Islamic State, analysts say.

Columnist Idiz pointed out that with Turkey bordering Iraq and Syria, however, Ankara is too important for its western nations to lose as an ally.

"I think it is a dilemma, because the general impression of Turkey in this regard is not very positive at the moment. Although Turkey appears a reluctant ally, it is nevertheless, an ally that NATO has to work with one way or another, because of Turkey’s proximity to the situation in Syria," said Idiz.

Turkish ties with western nations are under tense scrutiny, given the danger of Kobani falling to the Islamic State radicals. Although Ankara said it would allow passage of Iraqi Kurdish forces heading to Kobani to fight Islamic State, analysts said it may not be a big enough gesture to ease growing concerns.