Five environmental groups have filed legal challenges to the U.S. Army Corps of Engineers' plan to deepen the Delaware River shipping channel.
A lawsuit filed Thursday in U.S. District Court in Trenton seeks to enjoin the Corps from moving ahead without obtaining state permits.
The Delaware Riverkeeper Network and four other environmental groups also are seeking to intervene in similar suit filed by Delaware officials last month.
The Corps announced in October that it would begin the dredging in December or January without state permits, citing its duty to maintain navigation.
Supporters say the $300 million project is need to keep the ports competitive. Opponents say it will stir up toxic sediment and harm water quality.