More time. Either there is evidence or there isn't. Looks to me like he is stalling because he made a major twitter mistake.
This is one of many huge problem is when it comes to Trump. He's becoming more more like the boy that cried "wolf." What he is doing is he's taking the public's mistrust of the media and trying to exploit it. So he makes wild, unsubstantiated claims.
He's become like those who push anthropogenic climate change. Make claims first and then go searching for the evidence