Lukaku continues to be linked with Antonio Conte's side, having acknowledged a desire to play in Italy and hinted his future could be away from Old Trafford.
After meeting Nerazzurri officials regarding Lukaku on Wednesday, Pastorello told reporters: "Nothing new [to report]. We met each other to understand better the situation. We will see what [Inter] is going to decide.
"It is not on us. If the player wants to move [to Inter] they need to hurry. He [Lukaku] is a true target. It doesn't mean it will be official.
He added: "I think that the deal is not simple to reach, anyway."
Lukaku is contracted to the Red Devils until 2022 with the option of a further year and scored 12 Premier League goals in a disappointing 2018-19 campaign for the club.
Daniel James and Aaron Wan-Bissaka have arrived from Swansea City and Crystal Palace respectively, while the likes of Sporting midfielder Bruno Fernandes and Leicester City centre-back Harry Maguire have been linked.
In terms of departures, Ander Herrera has left on a free transfer and is expected to join Paris Saint-Germain, while Antonio Valencia is another who departed following the expiration of his contract with the club.
Matteo Darmian is could leave and there continues to be speculation over Paul Pogba's future, with the French World Cup winner a top target for Real Madrid.
Lukaku, meanwhile, scored 15 goals across all competitions for United in 2018-19 but it remains to be seen if he'll be remaining at Old Trafford next season.
His international manager Roberto Martinez has previously stated that it "is clear that he has to leave Manchester United", while Inter midfielder Radja Nainggolan's "see you soon" message teased a potential switch to San Siro.