WASHINGTON — A new report from a nuclear non-proliferation think tank contains satellite images showing activity at an Iranian site that was struck by Israel in March and that Israeli officials have said was used for nuclear weapons development.

What happened: The report from the Institute for Science and International Security (ISIS), published Tuesday, includes high-resolution satellite imagery taken by Vantor Technologies in September and October that shows what the institute described as a return to regular vehicle activity and ongoing earth-moving work at the Minzadehei compound, northeast of Tehran.

One area attacked in March shows ongoing earth-moving activity on a surface that appeared to function as a courtyard, where multiple craters were visible following the strike. Elsewhere at the compound, significant vehicle activity is visible between early September and early October. Cars are parked outside the security perimeter, while passenger vehicles and trucks can be seen inside.

The institute said the renewed activity could indicate “an effort by Iran to reestablish a nuclear weapons development capability and to reconstitute what was lost in the attack on the compound.”