ROME ― As European Union members seek closer ties, a series of simmering rows between France and Italy over a strategic shipyard, bringing peace to Libya, and ownership of undersea internet cables are undermining continental solidarity.

Stung by the pending exit of the U.K. from the EU, key members France, Germany, Italy and Spain have vowed to beef up military ties and use a new fund to bolster European defense industry integration. At a summit in Paris this week that tackled the surge of migration into Europe from lawless Libya, the four countries’ leaders discussed sending soldiers to Africa to oversee new resettlement camps.

But lurking behind the bonhomie was a number of rifts between Paris and Rome, which are threatening to ruin the party, starting with France’s opposition to the Italian takeover of key French shipyard STX.

French Economy Minister Bruno Le Maire said this week he was working to reach a deal with Rome after France temporarily nationalized the shipyard in July to prevent Italian shipbuilder Fincantieri from taking a controlling stake. State-controlled Fincantieri was due to take over after STX’s former owner, South Korea’s STX, went bankrupt and the Italian firm was named as the preferred bidder for a controlling stake. At the time, Fincantieri CEO Giuseppe Bono said the move would lay the foundation for much-needed naval yard integration in Europe, leading to what he called a “Naval Airbus.“

Following the blockade of the takeover by new French President Emmanuel Macron, tempers frayed in Rome, prompting the bid by Le Maire to work out a compromise in time for a French-Italian summit on Sept. 27. This week he hinted the deal Paris will offer could extend beyond an arrangement on Italo-French management of STX to wider cooperation on naval defense.

The suggestion could be a clever way of satisfying Bono’s ambitions for a naval Airbus, while in return allowing France to hold onto 50 percent of STX. Italian negotiators will, however, be wary of French proposals, mindful of the fact that France has happily bought up major Italian firms in recent years, from dairy firm Parmalat to jeweller Bulgari, while blocking the way to Italian acquisitions of French firms. As talks on STX continue, hostility has grown toward French media group Vivendi, which is the largest shareholder in Italy’s former state-owned telecoms giant Telecom Italia. Rome is now considering halting Vivendi control of a unit of Telecom Italia, Telecom Italia Sparkle, which manages 11 of the 21 undersea internet cables that pass through the Mediterranean Sea ― a key part of the global network of cables that make the internet possible.

Rome may invoke its Golden Power legislation, which allows it influence over takeovers of businesses considered strategic. The tension over takeovers has added to friction between Rome and Paris over lawless Libya, where Italy considers itself a key peacemaker and has been irritated by Macron’s recent efforts to steal the show. Italian irritation peaked as Macron hosted a meeting last month in Paris between Libya’s United Nations-backed prime minister, Fayez al-Sarraj, and his rival, military commander Khalifa Haftar, at which the two men agreed to call a cease-fire and hold elections early next year. That meeting, combined with the STX nationalization, created a “perfect storm among Italians, resulting in some public spats and a queue of French ministers flying to Rome to patch up relations,” wrote Jean Pierre Darnis, an analyst at the IAI think tank in Rome, in a paper this week titled “France, Italy and the Reawakening of Historical Rivalries.”

“Joint declarations and photo ops have not healed the wound, however, and tensions persist,” he wrote.

Many senior Italian political and military officials have not yet forgiven France for instigating the NATO bombing of Libya in 2011, which led to the ousting of former leader Moammar Gadhafi, pushing Libya into its current state of anarchy. Darnis wrote that France also had reason to be irritated with Italy: “A few years later, after the 2015 terror attacks in Paris, France triggered the solidarity clause of European Union treaty. Paris again asked for help on its missions abroad in order to relieve military forces needed for domestic terrorism prevention. Countries such as Germany and Ireland replied positively, whereas Italy did not.”

The bad blood, he wrote, is not helping Macron as he tries to stake a claim to leadership in Europe and give the EU a sense of purpose in the wake of Brexit.

“It is paradoxical to observe that while Macron’s proactive stance seems to be positively affecting relations in Europe, this new political cycle in France is becoming a black hole of ill feelings for Italy, which is uncomfortable with an activist France and its aspirations to gain a new form of leadership in Europe,” he wrote.