Italy should use it's "good offices" with Iran, including their trade relationship, to sway Tehran over its suspect nuclear program and its role in Afghanistan, a top US lawmaker said Monday.

"We believe that it's important for us to have very tough sanctions, we have to be united internationally on that subject, and that Italy can use its good offices and its communications with Iran to help bring us to a resolution of that most important issue," said Democratic House Speaker Nancy Pelosi.

Pelosi, just back from a trip to Italy and Afghanistan, said she and Italian leaders had discussed Iran's possible attendance at a special session of G8 foreign ministers on Afghanistan in Italy.

"You could say we sounded each other out on the involvement of Iran," she said, adding that Italy could help convince the Islamic republic to do more to stabilize its war-torn neighbor.

"Italy has a big commercial relationship with Iran, comparatively speaking, and I think we made it clear that we thought that it would be important to use their good offices to help resolve issues that we have with Iran," said Pelosi.