"We'll resume, and these people who are in these positions will resume [their jobs]," he said.
While Trimble said there was no way to guarantee 100 percent decommissioning, he said he was also concerned with weapons being funneled to other paramilitary groups.
"One of the concerns is the leakage of arms from the IRA to [splinter] groups," Trimble said.
He referred to the Aug. 1998 bombing in Omagh, which killed 29 people, and was conducted by the Real IRA, an IRA splinter group, which used IRA arms.
Currently, Unionist paramilitary groups have not decommissioned either, but Trimble said, they will turn in their arms in conjunction with the IRA.
At the conference, Trimble praised former U.S. Senator George Mitchell (D-Wash.) for his extensive work on the peace process. He said Mitchell he would not be making another peace-process trip.
"He's served his time--we've been amazed he has committed so much time," he said.
On his trip to the United States, Trimble visited U.S. National Security Adviser Sandy Berger on Monday in Washington and spoke at Boston College in addition to speaking at the ARCO Forum Tuesday. He left Boston last night on a flight back to Northern Ireland.