Can a thief steal during a trade?

[JaketheSnake]

Let's say that player 1 has an item in their hand they want to trade to player 2. In order to trade, he plays the card face up to carry it and then immediately trades with player 2. As a thief, can I interrupt the trade and attempt to steal the item? I suppose I could wait until the trade is over but it's good to know if a beneficial situation arises. Thanks!