According to Il Corriere dello Sport, Inter didn't pay Manchester United a bonus included in the agreement for Romelu Lukaku and the Red Devils want Lautaro Martinez or Milan Skriniar as compensation.
Lukaku joined Inter in a €74m move from Manchester United in the summer of 2019.
The Rome-based paper reports the Nerazzurri failed to pay a bonus in the region of €5m included in the agreement that saw the Belgian striker move to the Stadio Meazza.
According to the report, the agreement between the two parties came with a particular clause that sees Inter be debtors to the outstanding sum if they fail to pay one instalment. Inter still owe Manchester United €50m for Lukaku's transfer.
For this reason, Manchester United have reportedly asked Lautaro Martinez or Milan Skriniar as compensation for the missed payment.
Inter owners Suning have recently confirmed the commitment to the club's ongoing financial support but added theyare looking for "suitable partners" to support the Serie A giants financially.
Inter have also had problems with Achraf Hakimi's payment to Real Madrid and agreed to postpone the first €10m instalment to March 30.