Iran's weekend missile tests are 'a matter of concern', British Prime Minister Gordon Brown's spokesman said Monday, but stressed London's focus remained on Tehran's atomic programme. Iran on Monday test-fired its two long-range missiles, the day after the Revolutionary Guards fired several short- and medium-range missiles, some with multiple warheads, according to Iranian state media. 'The test firing of missiles at the weekend is of course a matter of concern, but we know the main issue remains Iran's nuclear programme,' Brown's spokesman told reporters. Iran's war games coincide with heightened tension with the West after the United Nations' nuclear watchdog revealed Friday that Tehran was building a second uranium enrichment plant. Western countries suspect Iran of seeking nuclear weapons, which Tehran denies. Iran and six world powers -- Britain, China, France, Germany, Russia and the United States -- meet in Geneva on Thursday to discuss Tehran's disputed atomic programme. Looking ahead to the meeting, Brown's spokesman said: 'All efforts must be to address the nuclear issue as part of that process.' 