Iran remains ready to engage in negotiations with world powers concerned about its nuclear programme, but only if the other parties show it due respect, its Foreign Ministry spokesman said on Wednesday.

We have always announced that we are ready for positive and useful negotiations but, as we have mentioned repeatedly, the condition for those talks to be successful is that we enter those negotiations in a stance of equality and respect for nations' rights, Ramin Mehmanparast was quoted as saying by the website of Iran's Arabic language al-Alam television.

Mehmanparast said a report published by the International Atomic Energy Organisation (IAEA) on Tuesday with what it said was credible evidence of military aspects of Iran's nuclear work, was merely the latest ploy by the United States to slander the Islamic Republic.

The Americans still think that to prevent a big nation like Iran from achieving its rights they should enter the wrong way and put pressure our nation and present baseless projects like the assassination plot of the Saudi ambassador in Washington, the human rights issue or pressuring the IAEA to issue an incorrect report, he said.

The last talks between Iran and the five permanent members of the U.N. Security Council, the United States, Russia, China, Britain and France, plus Germany, known as the 5+1 group, stalled at the start of the year.

Moves to revive the talks appear to have been hampered by the IAEA report and Washington's allegation that it foiled an Iranian plot to kill the Saudi ambassador to the United States, a charge Tehran denies.

Mehmanparast said the resumption of talks -- which, if successful could lead to an easing of sanctions on Iran -- depended on the actions of the other countries.

We will observe all the behaviour and moves of the 5+1 completely and we will make our final decision by studying the situation and their moves, he said.

If we feel the situation is ready for constructive talks with cooperation then we will announce our response.

The United States, Britain and France have all said they are looking at tightening sanctions on Iran.

(Reporting by Hossein Jaseb; Writing by Robin Pomeroy; Editing by Andrew Roche)