WASHINGTON (AP) -- Lawmakers provided a reality check Thursday to the Obama administration's optimism overs its trade agenda following some progress in key negotiations with Japan.

The administration said last week it narrowed differences on access to Japan's automobile and agriculture sectors. That's key to moving forward on a broader Pacific rim free trade pact.

But Democratic lawmakers including New York's Sen. Charles Schumer told the administration's top trade official that the 12-nation Trans-Pacific Partnership won't win congressional approval anyway, unless it also addresses alleged currency manipulation by Japan.

Trade Representative Michael Froman conceded at the hearing of the Senate Finance Committee that currency issues have not been discussed yet in TPP talks.

The committee's top-ranking Republican, Sen. Orrin Hatch, questioned the president's commitment to securing trade promotion authority. He said without it, the administration's ambitious trade agenda "will almost certainly fail."

Hatch is a co-sponsor of legislation to renew the so-called "fast track" authority of the president to negotiate a trade deal that would only face an up-or-down vote in Congress and would not be amended. Without that guarantee, it's harder for the other countries involved in the talks to make tough political decisions.

"The political clock is ticking and it won't be long before we lose the small window we have to pass significant trade legislation this year," Hatch told the hearing.

The TPP agreement is a key component of Obama's efforts to boost American exports to the growing economies of Asia, and assert U.S. influence in the region in the face of China's ascendancy.

But labor groups and lawmakers in Obama's own Democratic Party oppose TPP, arguing it could leave U.S. workers vulnerable to competition from countries with lower labor costs.

The deadline for the pact, which would cut tariffs and other barriers to trade, has been pushed back. But Froman said the administration will work to conclude negotiations during 2014. The U.S. and Japan are by far the biggest players in the pact that would account for more than one-third of global trade.

Froman said while the recent talks with Japan didn't result in an agreement between them, it was a "milestone" in tackling some sensitive market access issues.

"There's further work to do certainly but we think there was enough progress to give further momentum to the TPP negotiations overall," he said.