Serbian military and police officers have found a cache of highly powerful explosives not far from a pipeline that carries Russian natural gas from Turkey to Hungary, Serbian President Aleksandar Vucic said on April 5.

Vucic said that "two large packages of explosives with detonators" were found inside backpacks "a few hundred meters" from the Balkan Stream pipeline in Kanjiza, near the Hungarian border in northern Serbia.

"We have clues.... I just finished talking to [Hungarian Prime Minister] Viktor Orban. It's obvious that geopolitical games will not leave us alone," Vucic said without elaborating. Orban said he had called a unscheduled meeting of the country's defense council.

The incident occurred a week before Hungary's potentially pivotal April 12 parliamentary elections, in which Orban is seeking to extend his 16-year rule and opinion polls showing his party trailing the opposition Tisza party.

It also comes amid tension between Hungary and Ukraine over a separate route for Russian energy supplies, the Soviet-built Druzhba pipeline, which carries Russian oil across Ukraine and into landlocked Hungary and Slovakia.

The pipeline has been idle since it was damaged by a Russian missile in late January, with Budapest and Bratislava accusing Kyiv of delaying repairs for political reasons -- an allegation Ukraine denies.

Orban, whose sympathy for Russia puts him at odds with most of the rest of the EU over Moscow's war against Ukraine, raised the security level around Hungary's energy infrastructure in February. His government has claimed Ukraine is trying to trigger an energy crisis ahead of the elections.

Vucic praised Serbia's intelligence agencies and said: "We think we know which group the individuals who were supposed to take that final step in activating the explosives belong to. The intention was to send a political message. We will severely punish anyone we catch." He did not name or allude to any specific group.

Balkan Stream is an extension of the Turkstream pipeline. On March 19, the Serbian Army heightened security at the compressor station on the pipeline in Zabari, in eastern Serbia, after Vucic announced that the facility would be guarded by the military for security reasons due to the situation in the Middle East.

With reporting by Reuters and AFP