The Dutch clubâ€™s chairman Joop Munsterman wants double £4 million â€“ but Fulham wonâ€™t go much higher than their original bid.
Chadli, 21 has impressed in Holland and scored in both Champions League clashes with Tottenham last season.
Munsterman also says Fulham chief Martin Jol is interested in Chadliâ€™s team-mate Bryan Ruiz, 26.
But the FC Twente supremo said: â€œThe offer for Chadli is a half bid. And Bryan doesn't want to leave."