Satellite images of an Iranian military facility allegedly show attempts to clean the site of radioactive traces, diplomats have told AP. This adds to the stir over Iran’s nuclear activities, while Tehran insists on their peaceful nature.

Two of the diplomats told the news agency that the images show trucks and earth-moving vehicles. They claim the images indicate that crews were trying to clean up traces that could have come from the testing of a small neutron trigger used to set off a nuclear explosion.

A third diplomat could not confirm this, but stated that any testing of a so-called neutron initiator at the site could only be in the context of trying to develop nuclear arms, AP reports. The diplomats were speaking on Wednesday on condition of anonymity.

The diplomatic account comes as the international community puts more and more pressure on Tehran over allegations that it is trying to develop nuclear weapons. Tensions are also increasing with Israel considering a possible preventive strike on Iran’s nuclear facilities. The Israeli PM’s national security advisor recently said that it is unlikely that Iran will give up its controversial nuclear activities without “a real military alternative.”