This should be a blatant glimpse of the obvious...The agent is trying to buy more time in hopes that increased traffic/exposure will generate more offers.
While you didn't provide details, I would assume that you either made an early, pre-emptive offer OR a weak offer.

Apparently the agent, seller or possibly both either conciously or sub-conciously don't feel that your offer is strong enough to ratify and want to continue to market the home in search of stronger offers.