COLOGNE, Germany — European Union officials have offered a positive initial assessment of a recent U.S. request to join the bloc’s program for improving transportation pathways for military forces on the continent.

Stefano Sannino, secretary general of the European External Action Service, said he is “very pleased” with the Pentagon’s initiative to partake in a Permanent Structured Cooperation program on military mobility.

“I suppose, and I hope, that it will work fine,” Sannino said, adding that Brussels would “devote energy and attention” to seeing the application through.

The U.S. request, along with similar ones by Canada and Norway, marks the first time that a non-EU member has gone through the motions of seeking a role in one of the bloc’s 47 defense cooperation projects. Initiatives under the PESCO banner are primarily meant to streamline capabilities among member states, but exceptions can be granted to admit outsiders.

Officials on both sides of the Atlantic view U.S. participation in the military mobility initiative as a trial balloon for future cooperation under EU rules. That is partly because all relevant member states are represented in that effort, led by the Netherlands, thereby exposing everyone to the decision.

In addition, the topic of military mobility is largely about political decision-making and bureaucratic wrangling rather than teaming up on new weapons spending, which is a more conflict-prone subject in Europe.

“We’re at the start of it,” Sannino said at a March 12 online event hosted by the European Council on Foreign Relations, referring to the status of discussions. He framed Washington’s request as an opportunity to put into action a “political willingness” toward a U.S.-EU defense relationship.

Still, there are no guarantees, as the EU can be fickle.

When asked about the state of play, a Dutch defense official, listed as a point of contact in the PESCO catalog, declined to comment, describing the matter as an “internal process.”

Since Washington submitted its cooperation request on Feb. 25, all project members had an initial meeting that leaned favorable, a German defense official said. The idea is to tee up a formal decision during a May 6 meeting of the Council of the European Union.

Some European officials remain apprehensive about cooperating with the U.S. on the bloc’s internal effort to become more militarily independent. As the world’s largest and most expensive military force, the United States could, knowingly or not, end up detracting from Europe’s vision of autonomy if given too prominent a role, the thinking goes.

That is why the prospective military mobility cooperation is considered a fairly safe bet: There is no danger of importing U.S. laws affecting weapon acquisition and exports, for example, a German official said.

Harmonizing cross-border transportation for military forces in Europe, many of them American, has long been on the trans-Atlantic agenda in a NATO context. Russia’s annexation of Crimea in 2014 has reinvigorated alliance efforts to be able to quickly ship forces eastward in the event of a conflict.

But rail lines remain incompatible across countries, bridges need repairs and the red tape of customs clearance remains a hindrance, according to military officials.