The collective bargaining agreement between the International Longshoremen's Association (ILA) and the U.S. Maritime Alliance (USMX) was set to expire on Sept. 30.
"In taking this significant step, the parties emphasized that they are doing so 'for the good of the country' to avoid any interruption in interstate commerce," George Cohen, director of the Federal Mediation and Conciliation Service, said in a statement.
The FMCS is an independent U.S. agency, based in Washington.
The negotiations will continue under the auspices of the FMCS.
Some shippers have accelerated freight deliveries to avoid the possibility of goods languishing in East Coast and U.S. Gulf Coast ports in case of a strike.
About 20,000 longshoremen who handle container cargo from Maine to Texas are represented by the ILA. USMX is an alliance of container carriers, direct employers and port associations along the U.S. East and Gulf coasts.
Talks over the contract restarted on Monday, after breaking down in late August.
The timing, location and substance of the talks will not be released because of the sensitive nature of the dispute, the agency said.
ILA and USMX representatives were not immediately available for comment. (Reuters)
