(Updated 6 Dec 2010, 7pm.)

The US-Korea PTA is back on the table, as US automakers won some concessions from South Korea:

The new supplement agreement allows 25,000 cars per U.S. automaker to qualify for entry into the South Korean market based on U.S. safety standards. That is about four times the amount agreed to under the deal struck in 2007.

It also allows the United States to keep a 25 percent tariff on trucks until the eighth year, instead of beginning to reduce it in the first year. The United States will still have to eliminate the duty in year 10 of the pact.

South Korea is no longer required to eliminate immediately its 8 percent tariff on U.S. auto imports, but will reduce it to 4 percent for four years before eliminating it.

Seoul will still immediately eliminate a 10 percent tariff on U.S. trucks under the revised pact.

South Korea was given an additional two years — until 2016 — to eliminate duties on some U.S. pork products.

The deal needs to be ratified by the Korean National Assembly and the US Congress. Last month, Jeff Schott said that the deal could still be “fast tracked” to Congress because it was signed by President Bush before his trade promotion authority expired. I do not know if yesterday’s revisions (“supplement agreement”) also qualify under the old TPA or if the revised PTA will be subject to Congressional amendments.

UPDATE: Reuter’s Doug Palmer says that White House and USTR both say the revised deal is eligible under the old trade-promotion authority.