Chief negotiators from countries involved in the proposed Trans-Pacific Partnership free trade initiative wrapped up their latest round of negotiations in Guam on Wednesday, without setting a date for a ministerial meeting to reach a broad agreement.

The 12 countries in the negotiations have called off a ministerial meeting scheduled for this month, amid uncertainties over passage of a key U.S. bill for fast-tracking the trade deal, seen as necessary before reaching a TPP deal.

According to negotiation sources, the United States, which leads the TPP, suggested holding a ministerial session in late June, but the other TPP countries showed reluctance to the idea as Washington has yet to have Congress pass the so-called trade promotion authority (TPA) bill.

No major progress was made on contentious issues during the chief negotiators' meeting, which began May 16, partly because the TPA has proven elusive, the sources said.

The TPA legislation would help enable U.S. President Barack Obama to seal a TPP deal by allowing Congress to vote only to accept or reject the pact in its entirety. Without the TPA, other negotiating countries are seen as unwilling to offer concessions on the outstanding issues for fear the U.S. Congress could reject the deal.

The 12 countries involved in the talks are Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.