WASHINGTON (AP) -- A top Army Corps of Engineers official told federal lawmakers the agency can't legally reverse its decision to reduce the Missouri River's flow into the rain-starved Mississippi River.

But Sen. Dick Durbin of Illinois says Army Assistant Secretary Jo-Ellen Darcy did tell him and senators from Iowa and Minnesota on Thursday that the corps will see if the flows curbed last week by the Corps can be tweaked to help keep the Mississippi safely navigable.

Lawmakers from Mississippi River states have argued that the waterway's critically low levels could threaten to bring barge traffic to a halt.

Grain, corn, coal, petroleum and chemicals are all typically shipped on the river. That's partly because the volume is so high that using trucks or trains would be far more costly