Two of the largest and most influential countries in the Middle East, Turkey and Iran, are apparently softening their head-to-head rivalry that has persisted for centuries, deciding to conduct a joint counterterrorism fight against the PKK terrorist organization. The possible rapprochement between the two countries has also raised questions regarding the scope of the cooperative effort and whether it would be limited solely to the PKK or extend to further policy convergence between the two countries.

Although the two states have long been fighting separately against the PKK and its Iranian offshoot the Kurdistan Free Life Party (PJAK), things may have begun to change since Iranian Chief of Staff General Mohammad Hossein Bagheri's visit to Ankara last week.

Speaking to reporters on Monday, President Recep Tayyip Erdoğan said that Turkey and Iran have discussed the likelihood of conducting a joint operation against the PKK, speaking during Gen. Bagheri's visit to the Turkish capital.

"A joint operation with Iran against terrorist groups that pose a threat [to the region] is always on the agenda," President Erdoğan declared. "We have discussed the details regarding the scope of the operation among ourselves. There is damage being done by the PKK and its Iranian offshoot. We will conduct these discussions with the understanding that the threats can be defeated with cooperation from both countries and in a short period of time," he added.

However, experts have said that Turkey and Iran might have different expectations regarding the cooperation. Iranian expert Ferhad Rezai, from the Centre for Iranian Studies in Ankara believes that the prospect of a possible end to the PKK raises difficulties for Iran. "Tehran is not interested in seeing an end to the PKK as it would deprive Iran of important leverage it uses to put pressure on Turkey," Rezai said while underlining that Iran's cooperation with Turkey will likely be a tactical and temporary move as the PKK is instrumental for Iran in the Middle East.

Galip Dalay, research director of the Al-Sharq Forum, said that there are prospects for Turkey and Iran regarding the potential collaborations against the PKK. ‘‘To some extent, this has been facilitated by Iran's new understanding that the PKK's Syrian offshoot the PYD [the Democratic Union Party] is transitioning from Iran's orbit to the U.S., in terms of influencing regional affairs. This has led Iran to reevaluate its approach to these organizations," he said.

Dalay also drew attention to the fact that Iran has not yet made the decision to entirely challenge the PKK and its affiliates, the PYD and PJAK, because Iran does not perceive the same level of threat from these organizations as Turkey does.

‘‘Furthermore, the PKK and PJAK have not made any declaration that they are terminating the ceasefire agreement they reached with Iran in autumn of 2011. For this reason, Iran might want to teach the PKK, the PYD and PJAK a lesson or two. But, this does not mean that Iran will go against them in a full-fledged manner."

In the meantime, the Iranian side has begun sending mixed signals about the possible counter-PKK operation.

The Iranian Revolutionary Guards (IRGC) denied on Tuesday that it has carried out any operations outside of Iranian borders. Iran's Mehr news agency published a statement from the IRGC in which the organization denied participating in joint Iranian-Turkish operations against the PKK outside of Iranian borders. However, the Iranian Guards asserted: "As in the past, we would have strongly opposed any group, cell or person who attempted to infiltrate Iranian territory for the purpose of carrying out anti-security or terrorist activities."

Responding to questions about how a possible counterterror operation against the PKK could provide an opportunity for further policy convergence between the two countries, Dalay said that the interests of both countries are far from meeting, adding that the two countries have different policies on Iraq, Syria and the larger region.

Rezai echoed these thoughts, adding: "If Turkey continues its support of the opposition forces [in Syria]. …Iran could renew its support for the PKK and will turn a blind eye to PKK terrorist activity along its border with Turkey."

Dalay also stressed that there is signal of change regarding Iranian policy, saying: "There is a change. The convergence that is taking place between the countries is on the level of concerns and challenges." He went on to say: "Both [sides] are worried about the U.S. policy towards Syria. Both are concerned about regional Kurdish geopolitics. Also, both sides are unhappy in the face of the Kurdish drive for independence in Iraq, albeit for varying reasons on different levels. These issues provide common ground for Turkey and Iran to build on," he concluded.