Iran fired a Shahab-3 medium-range missile on Wednesday, a US military official said, playing it down by saying that it did not pose a threat to American or other western shipping or military bases in the region.

The missile was launched from the southern coast of Iran and landed east of Tehran, the official said on Thursday, adding that it flew about 1,100km, or about 680 miles, and stayed inside Iran for the entire flight.

The official, who spoke on the condition of anonymity to discuss intelligence analyses, said that American officials had been closely monitoring the test site as Iran prepared the missile for launch.

Despite the Pentagon’s effort to minimise the strategic importance of the launch on Wednesday, it appears to be a political statement by Iran, acting both as a carefully calibrated effort at escalation — and as a message to Europe.

Missile launches are not forbidden under the 2015 nuclear accord reached between Washington and Tehran, which is one of President Trump’s complaints about the agreement he abandoned last year.

But a UN Security Council resolution, passed just as the agreement was reached, says that “Iran is called upon not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology.”

Secretary of state Mike Pompeo has demanded that Iran cease all missile launches and testing. Iran says it is under no obligation to do so, and notes that because it has no interest in nuclear weapons, it is not violating the wording of the UN prohibition.

Last week in New York, Iran’s foreign minister, Mohammad Javad Zarif, said that if the US wanted to discuss missile limitations, it should begin by not supplying Saudi Arabia, the UAE and other Arab states with missiles that threaten Iran. The test on Wednesday seemed meant to drive home the point that Iran had no intention on giving up on its own missile fleet.

The Shahab-3 is hardly a new weapon — it has been in the Iranian arsenal for two decades. Based on a North Korean design, called the No-Dong, it can fly about 1,000km. Variants can range farther, capable of striking the edge of Europe.

But more important, Israel and a number of western experts say a nuclear weapon can be fashioned to fit in the missile’s nose cone. The test launch may also be meant to demonstrate that American efforts to sabotage the Iranian missile programme, chiefly with bad parts, are not impeding its development.

The missile launch in Iran came within hours of North Korea’s launching of two short-range ballistic missiles off its east coast on Thursday.