HELSINKI — The deepening in bilateral defense collaboration between non-aligned Nordic states Sweden and Finland is expected to include the establishment of joint units and the sharing of naval and Air Force infrastructure.

Moreover, Sweden remains interested in selling the JAS Gripen-E to Finland, which has begun the process of replacing the Air Force’s F/A-18 C/D Hornet aircraft, which are scheduled to be retired between 2025 and 2030.

Although government officials remain tight lipped, the increasingly closer military cooperation between Finland and Sweden advances the possibility that Finland may opt to pursue a replacement strategy that includes two different NATO-compatible fighter types, one of which could be the Gripen E.

Ongoing defense negotiations between Finland and Sweden are focused on removing outstanding legal impediments that prohibit deeper military collaboration.

It is expected that future bilateral agreements will not only cover joint tasks and the sharing of naval ports and air bases, but will also allow each country to aid the other in the event of an armed attack.

In a joint statement released Jan. 10, Finnish and Swedish Prime Ministers Juha Sipilä and Stefan Löfven underscored the need to build a bilateral military collaboration structure that is practical and usable, warning that European security faces its gravest threat since the Cold War era.

"Finland and Sweden both operate outside of military alliances. We believe that this policy serves us well. We must rely on this experience in our assessment of the challenges currently facing us. Our military non-alignment contributes to the stability and security of Northern Europe as a whole. Even though we are not members in NATO, we cooperate with the organization. We have also a strong trans-Atlantic link," the statement read.

The unified approach being taken by Sweden and Finland to regional and European defense and security challenges suggest that neither country is eager to rush into joining a major military alliance such as NATO, said Ulf Kehl, a Berlin-based political analyst.

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"Despite the recent talk over Finland and Sweden joining NATO, if this does happen it is likely to be a process far in the distant future. It seems clear that while both countries want to develop closer military ties with NATO and the European Union, neither state is in any hurry to abandon their present neutrality status," Kehl said.

The more immediate need for both Sweden and Finland is to build the basis for a stronger regional military-security alliance with NATO-neighbors Denmark, Norway, Estonia, Lithuania and Latvia, said Kehl.

"The traditional threat of Russia in the High North and the Baltic Sea remains, but it is the new and emerging threats, from ISIL and cyber warfare, that are also driving cooperation forward," Kehl said.

The so-called "NATO-question" on collaboration and possible future membership will remain a subject open for dialogue between Sweden and Finland, said Margot Wallström, Sweden's foreign minister.

"It's important that we work closely together on these important issues. We must try to maintain a common position [on NATO] as long as possible," Wallström said.

Sweden and Finland are continuing to deepen cooperation with NATO. In December, Sweden extended permission allowing for NATO AWAC surveillance aircraft to fly over Swedish airspace. The new six-month extension period will expire on May 31.

The NATO aircraft have the capacity to track other aircraft at distances of up to 250 miles and will fly over Swedish airspace on routes between Norway and Poland.

As part of defense-deepening, Finland and Sweden aim to remove the existing legal impediments that prohibit closer bilateral military cooperation, said Jussi Niinistö, Finland's defense minister.

"What is clear is that there should not be statutory limitations that prevent consideration of providing Finnish resources to assist Sweden, or conversely, to prevent Finland from accepting help offered from Sweden," Niinistö said.

The inter-state dialogue on defense cooperation is expected to include the possibility of joint procurements.

However, the Finnish government has so far stopped short of declaring a special interest in purchasing the Gripen as part of its defense engagement with Sweden.

"There has been some speculative noise in Sweden that Saab would do a deal with Finland even in a theoretical contract situation where Finland chose to acquire two different aircraft types. Finland’s fighter replacement process has just commenced, so it is much too early to predict an outcome here," said Kehl.

The Finnish Ministry of Defense launched its HX Fighter Program at the end of 2015 on the back of an Expert Working Group report in June 2015 that recommended acquisition of a multirole fighter over carrying out an additional upgrade to the Air Force’s 61 F/A-18C/D aircraft.

The Boeing F/A-18E/F Super Hornet, Dassault Rafale, Eurofighter Typhoon, Lockheed Martin F-35 and the Saab Gripen-E comprise the five fighter type candidates being considered by the HX Fighter Program.

The request for information (RfI) concerning the HX Fighter Program is due to be sent to aircraft manufacturers in March and replies are required by Oct. 31.