VIENNA - The UN nuclear watchdog said on Wednesday it had failed to secure an agreement with Iran during two days of talks over disputed atomic activities and that the Islamic Republic had rejected a request to visit a key military site.In the second such trip in less than a month, a senior team from the International Atomic Energy Agency (IAEA) had traveled to Tehran to press Iranian officials to start addressing mounting concerns that the Islamic Republic may be seeking to develop nuclear weapons.The IAEA named Parchin in a detailed report in November that lent independent weight to Western fears that Iran was working to develop an atomic bomb, an allegation Iranian officials reject."It is disappointing that Iran did not accept our request to visit Parchin. We engaged in a constructive spirit, but no agreement was reached," said IAEA Director General Yukiya Amano.Earlier, Iran's envoy to the IAEA, Ali Asghar Soltanieh, told the country's ISNA news agency that Tehran expected to hold more talks with the UN agency, whose task it is to prevent the spread of nuclear weapons in the world.But Amano's spokeswoman, Gill Tudor, made clear no further meetings were planned: "At this point in time there is no agreement on further discussions," she said.The outcome seems likely to add to already soaring tension between Iran and Western powers, which have ratcheted up sanctions on the major oil producer in recent months."During both the first and second round of discussions, the agency team requested access to the military site at Parchin. Iran did not grant permission for this visit to take place," the Vienna-based IAEA said in a statement after the Feb 20-21 talks.