NEW YORK, Sept 24 (Reuters) - Marathon Petroleum ( MPC )

and the Teamsters union, which represents refinery workers in

Detroit, Michigan, are at a standstill as negotiations for a new

labor agreement stagnate and the strike at the plant enters its

third week.

More than 200 Teamsters at Marathon's Detroit refinery

called for an economic strike on Sept. 4 after nine months of

pay- and safety-related negotiations and mediation with Marathon

failed to reach agreement. The prior contract expired in

January.

"Unfortunately, the parties have not reached an agreement,"

a Marathon spokesperson said.

Marathon representatives and the union had several

negotiating sessions under a federal mediator, including this

past Friday and Sunday.

"We continue to be in regular communication with the federal

mediator; however, at this time, no additional negotiation

meetings are scheduled."

Teamsters Local 283 represents 273 workers at the Detroit

refinery, 95% of whom authorized the strike.

President of Teamsters Local 283 Steve Hicks said Marathon

representatives walked away from the bargaining table at the

latest round of contract talks this past weekend and canceled

the negotiating session that was due this Friday.

The Detroit refinery started planned turnaround activities

earlier this month.

The 140,000 barrel-per-day (bpd) Detroit refinery is one of

Marathon's 13 refineries with approximately 2.9 million bpd of

crude oil refining capacity.