South Korea and the United States held talks on Thursday to review labor and environmental standards included in a sweeping trade deal struck earlier in the year in order to help its passage in the U.S. Congress.

A small team of U.S. trade negotiators held talks in Seoul and will continue discussions on Friday on changes Washington is seeking in seven sectors, including the contentious area of pharmaceuticals.

The U.S. side explained its revised proposal and we were mostly asking question, South Korea's deputy chief trade negotiator Lee Hye-min told reporters after the meeting.

The pact -- the biggest U.S. trade deal in 15 years -- was reached in April. But U.S. Congressional Democrats reached an agreement with the White House in May that paved the way for approval of the Republican Bush administration's free trade deals if enforceable labor and environmental provisions were added.

South Korean officials say they anticipate there will be no major changes and expect the pact will be signed on June 30 as scheduled in Washington by the two sides' top trade officials.

The United States was seeking changes to conflict resolution mechanisms in the event either side failed to meet international labor and environment standards, Lee said.

The U.S. proposal did not involve the heated areas of automobiles or farm products, Lee said.

The deal is expected to boost South Korea's economy as much as 6 percent over the next 10 years and create 340,000 jobs, government-affiliated think tanks say. The pact also has the backing of many U.S. financial companies and agricultural firms.

But it has raised hackles among South Korean farmers because it will open wider the heavily protected agricultural market. For their part, U.S. automakers fear a fresh wave of Korean imports.

The trade deal may be good for U.S. farmers, but for us, it is no different than a death sentence, said South Korean farmer Shin Pil-joo.

(With additional reporting by Jack Kim)