SAVANNAH (AP) — Interest groups and the public are getting 15 extra days to submit comments on a $653 million proposal to deepen the Savannah harbor.

The Army Corps of Engineers said Tuesday the new deadline for public comments is June 5. The original 30-day comment deadline was later this month.

The Army Corps and the Georgia Ports Authority want to deepen 38 miles of the Savannah River by 5 feet to allow larger cargo ships to reach Savannah’s seaport. Supporters see great economic benefits, while critics worry about the environmental consequences.

Public comments will be included with the final draft of the Corps’ planning reports issued last month. Supporters of the harbor expansion hope to win final approval before the end of 2012.