Turkey and Iraq reached a landmark security deal to crack down on Kurdish militants holed up in the mountains of northern Iraq.

The agreement comes as the two countries work toward building a major trade route and restarting a key oil pipeline running from northern Iraq to Turkey’s coast.

Turkey welcomed a decision by Iraq to label the Kurdistan Workers’ Party, or PKK, a “banned organization” and the two countries discussed measures against the group, according to a joint statement late Thursday.

Ankara has long sought to prevent the Kurdish militants — labeled as terrorists by the US and European Union — from using northern Iraq as a springboard for attacks in their decades-long war for autonomy in Turkey’s largely Kurdish southeast.

Turkey’s looking to expand its military operations against the PKK in Iraq. President Recep Tayyip Erdogan — who’s expected to visit Baghdad next month — is courting nationalist voters ahead of local elections on March 31. The cross-border operation, which is expected to target PKK hideouts on Mount Gara, is unlikely to start before the winter snow melts in April or May.

Turkey ultimately aims to create a security corridor up to 40 kilometers (25 miles) deep along the joint border.

Iraq and Turkey are also seeking to convince Gulf states to help finance a $17 billion trade route stretching from Iraq’s southern Basra province to Turkey, and then on to Europe.

They say the corridor could provide an alternative for sending goods from Asia to Europe, given the difficulties in shipping through the Red Sea as a result of attacks on vessels by Houthi militants. Still, India, the United Arab Emirates and the US have started work on a similar route, which may lessen the need for Turkey’s proposal.

Erdogan’s visit to Iraq and the security deal could help resolve a dispute that has halted oil shipments from Iraqi Kurdistan to the Turkish port of Ceyhan over the past year. That has cut off nearly half a million barrels of crude per day from global markets.