U.S. Vice President Joe Biden has called for Japan to make further concessions in the ongoing Pacific Rim free-trade talks so the two sides can reach a bilateral agreement before Prime Minister Shinzo Abe's trip to Washington in late April, a senior Japanese lawmaker said Tuesday.

During a conversation with Masahiko Komura by phone last week, Biden urged Japan to show more flexibility on the issue of market access for autos, one of the biggest sticking points in the Trans-Pacific Partnership negotiations, according to the vice president of Abe's Liberal Democratic Party.

Speaking at an LDP meeting, Komura added he told Biden that both Japan and the United States need to show flexibility to reach a bilateral deal — seen as vital to realizing the 12-nation TPP initiative.

Komura, a former foreign minister, also said he expressed hope during the conversation that Congress will grant President Barack Obama fast-track authority to sign trade deals.

Abe will make an eight-day official visit to the United States beginning April 26. He is slated to meet with Obama on April 28.