Japan and the United States believe it will be difficult for World Trade Organization to strike an accord on the details of farm and industrial goods trade liberalization by the April 30 deadline, Japanese officials said Friday.

Economy, Trade and Industry Minister Toshihiro Nikai and U.S. Trade Representative Robert Portman discussed prospects for the negotiations during a one-hour teleconference Thursday night. They agreed that they would have to closely cooperate to lead the multilateral talks, they said.

"I feel Portman believes steep slopes and mountains still lie ahead before reaching a deal by the end of April," Nikai said to reporters Friday morning. "He told me that the United States expects Japan to exert leadership."

Portman briefed the trade minister about the talks between among the U.S., the European Union and Brazil between March 31 and April 1 in Rio de Janeiro, and told him no major progress had been made, Nikai said. WTO Director General Pascal Lamy also joined the negotiations, according to the officials.

The USTR has also informed Agriculture, Forestry and Fisheries Minister Shoichi Nakagawa about the meeting in Brazil, they said.

The WTO economies have set an end-of-April deadline for producing an outline for a comprehensive trade deal, with numerical goals, in the agricultural and industrial areas. This will help conclude the current negotiations, known as the Doha Round, by the end of the year as earlier agreed.

But sharp differences between the developed and developing countries, as well as food importers and exporters, have prolonged the talks, causing WTO members to repeatedly extend the self-imposed deadlines.

Meanwhile, Portman showed his interest in Japan's proposal for launching a 16-nation free-trade zone in Asia, Nikai said.