A shipping group asked a US labor agency Thursday to compel talks with a union ahead of a potential strike that could impact the national economy weeks before the presidential election.

The United States Maritime Alliance (USMX), which represents shipping companies and terminal operators, said it filed an unfair labor practice complaint against the International Longshoremen's Association (ILA).

The complaint lodged with the National Labor Relations Board seeks to require "the union to resume bargaining -- so that we can negotiate a deal," USMX said.

Tens of thousands of port workers on the East and Gulf Coasts could walk off the job on October 1 if there is no contract, threatening turmoil before the November 5 vote.

The USMX statement cited the ILA's "repeated refusal to come to the table," adding, "we have a shared history of working together and are committed to bargaining."

The ILA did not immediately respond to a request for comment.

The union has previously accused the USMX of a "misleading publicity campaign."

"The two sides have communicated multiple times in recent weeks," said a September 23 ILA statement. "USMX continues to offer ILA longshore workers an unacceptable wage increase package."

The NLRB did not immediately respond to a request for comment.