Ukraine wants the EU to quickly outline a package of sanctions to use against Russia if the Kremlin chooses to step up its military aggression against Kyiv.

The call comes as concerns grow about the intentions of President Vladimir Putin and the increasing Russian troop presence near the Ukrainian border.

“If you at least set up or pull together a serious package of sanctions and you let Russia know this is what’s going to happen then that will deter Russia,” Dmytro Kuleba, Ukraine’s foreign minister, said.

“At this point our partners maintain the constructive ambiguity approach, they say that consequences for Russia will be severe and unprecedented and so far and so on, but they don’t go into details,” Kuleba CNBC’s Hadley Gamble Thursday, making clear his frustration with EU leaders.

The heightened tensions at the Ukraine border with Russia are being discussed by EU heads of state in Brussels on Thursday. It is so far unclear how far they are willing to go to address Russia’s military activity, but some EU leaders share Ukraine’s view that a package of sanctions needs to be developed soon.

In fact, some European capitals have even suggested that Nord Stream 2, the contentious gas pipeline that bypasses places like Ukraine and Poland, should feature on a potential sanctions list against Russia.

“I think we will raise this issue because this is one of the instruments which could be very strong in relation to Russia,” Gitanas Nauseda, the president of Lithuania, said at his arrival in Brussels on Nord Stream 2.

This energy project is meant to bring gas into Europe from Russia to Germany. However, the pipeline has not yet gained full regulatory approval and has been embroiled in political controversy.

On the one hand, some politicians, notably in Germany, argue that the project is an economic matter. Critics of the pipeline, however, say it increases Europe’s dependency on Russia.

Germany’s Foreign Affairs Minister Annalena Baerbock has said that Nord Stream 2 should not be allowed to operate if there’s more Russian aggression toward Ukraine.

Putin has previously pressured EU officials to approve the project, saying it is an easy solution to bring down energy costs in the region.

A spokesperson for the Kremlin said Thursday that Nord Stream 2 was in the interests of Russia and Germany, Reuters reported.

“It would be important that we could also decide that Nord Stream 2 is on the table [in terms of sanctions],” Arturs Karins, the prime minister of Latvia, also said in Brussels.

“If there is heightened military activity then this project would be turned off,” Karins added

However, not everybody agrees. Finish Prime Minister Sanna Marin told CNBC that “it is important to keep energy policy out of the conflict.”

The different views highlight the difficulty for EU leaders to find common ground on how to address aggression from Russia.

Slovenia Prime Minister Janez Jansa said that the “military concentration” taking place close to Ukrainian borders is “not normal for regular military exercises.”

“There is no doubt that Russia is using military power to make pressure,” he told CNBC.

In the meantime, some EU leaders think that dialogue is needed with Russia to prevent any further escalation.

“I strongly believe … we need to speak with Russia also,” Xavier Bettel, the prime minister of Luxembourg, told CNBC.

He added that the format of these talks are not important as long as they are effective.

It’s possible that France and Germany reach out to Moscow and Kyiv in the hope of finding a solution. It is unlikely that these talks with include the whole of the EU in the short term.