Bulgaria will present new evidence pointing to Hezbollah involvement in a bus bombing that killed five Israelis and a local last year, the country’s interim prime minister said Wednesday, suggesting the move should help push the European Union to label the Iran-backed group a terror organization.

Bulgaria earlier published a report laying the blame for the attack on a bus at the Burgas airport firmly on Hezbollah, but acting prime minister Marin Raikov told reporters Wednesday that some EU countries wanted to see more evidence before blacklisting the Shi’ite group.

“We will continue the investigation. We will continue to work on this very seriously, very actively. We will provide the needed evidence,” he told reporters from NATO headquarters, according to Reuters.

Earlier this month, Raikov said that Sofia would not take the lead in getting the EU to act against Hezbollah, reversing the stance of the previous government, which had published the report and urged Europe to label the group a terror organization.

Raikov was named interim prime minister in early March, after the fall of the last government over poverty and corruption allegations. New national elections are scheduled for May 12.

Bulgaria’s interior minister Tsvetan Tsvetanov announced in February that two men with links to the terrorist organization Hezbollah were implicated in the terrorist bus bombing on July 19 at the airport in Burgas, which targeted a bus of Israeli tourists and left five Israelis and their Bulgarian bus driver dead.

Hezbollah also financed the bomb attack on the bus, according to the Bulgarian investigation.

US and Israeli officials have said the EU should blacklist Hezbollah. Its inclusion would make it illegal for Hezbollah sympathizers in Europe to send money to the group, which the United States and Israel list as terrorist.

Earlier this week, Bahrain’s parliament passed a bill labeling Hezbollah a terror group.

Bahrain’s ruling class are mostly Sunni and reject moves by Iran, which is Hezbollah’s main patron, along with Syria.

Although the EU has considered adding Hezbollah to its list of terrorist organizations, many European governments have argued that such a move could ignite Middle East tensions.

In Bulgaria, as well, opposition groups have said that pushing to blacklist Hezbollah could open up Bulgaria to more attacks.

Israel has repeatedly urged the EU to list Hezbollah as a terrorist group.

JTA contributed to this report.