LONDON - Iran's medium-range missile test Wednesday is a matter of "serious concern" and makes the case for "moving further on sanctions," British Prime Minister Gordon Brown said.

Brown is in Copenhagen for the United Nations climate summit, where he discussed the development with UN Secretary General Ban Ki-moon.

"I have expressed to him and he has also expressed concern about the test of a long-range missile by Iran," Brown said, according to his Downing Street office in London.

"This is a matter of serious concern to the international community and it does make the case for us moving further on sanctions.

"We will treat this with the seriousness it deserves."

Iran successfully test-fired an improved version of its Sejil 2 medium-range missile which it says can reach targets inside Israel, state television announced.