In a development significant both for its timing and its content, Iran unveiled on Sunday a new cruise missile that it claimed would extend the Islamic Republic’s range by 25 percent, placing locales as distant as Budapest, Warsaw, and Athens within striking distance.

The Iranian revelation, complete with videos of a missile launch, come amid Tehran’s negotiations with the six world powers over its nuclear program and infrastructure.

Israel has long urged the negotiating world powers to include Iran’s growing missile-development program within the framework of the negotiations — a demand that Tehran has rejected out of hand.

“By the way,” Prime Minister Benjamin Netanyahu told members of Congress in a controversial address last week, “if Iran’s intercontinental ballistic missile program is not part of the deal, and so far, Iran refuses to even put it on the negotiating table,” then Iran, if it attains a nuclear arsenal in the future, will have the means to deliver it “to the far-reach corners of the earth, including to every part of the United States.”

The Soumar missile, as it is known in Iran, is a copy of the Soviet Kh-55, which was stolen from the Ukraine in 2001 and apparently reverse engineered in Iran.

Tal Inbar, the head of space research at the Fisher Institute for Air and Space Strategic Studies, called the new cruise missile and the increased range it represents [2,500 kilometers] “a dramatic shift.”

He said in an email statement that the Soumar, like other cruise missiles, flies at a low altitude, making it hard for radar to detect.

The payload the missile is able to carry is reportedly in the 200-kilogram range, meaning that it is nowhere near capable of delivering a nuclear device.

Nonetheless, it is a significant development, said Inbar, who has monitored the Iranian missile development program for years.

The inclusion of European capitals within Iran’s missile range triggers further discussion about US plans to station missile defense systems in Europe. Russia has long contended that Iranian missiles threaten neither Europe nor the US, Inbar wrote, and therefore it is “a very interesting move — if it was taken without Russian consent.”

Moreover, the unveiling of these new missiles, a decision almost certainly approved by Iran’s supreme leader Ayatollah Ali Khamenai, taken as the nuclear negotiations reach a pivotal juncture at the end of March, “is a significant signal,” Inbar wrote, “especially in light of the Iranian proclamations that the matter of missiles would not be up for negotiation.”