WASHINGTON -- Top U.S. diplomat John Kerry will push Malaysia to redouble its efforts against human trafficking on an upcoming visit for regional security talks, a senior State Department official said Friday.

Secretary of State Kerry's visit, starting Wednesday, comes a week after the department faced a storm of protest for lifting Malaysia off its trafficking blacklist. U.S. lawmakers and human rights activists say the decision was intended to smooth the way for a trade agreement among 12 Pacific rim nations, including Malaysia.

The official maintained there's been progress in Malaysia's performance, but it needs to do much more, in expanding prosecutions and meeting standards laid out in U.S. anti-trafficking legislation. The official was briefing reporters on condition of anonymity under ground rules set by the department.

Like neighbouring Thailand, Malaysia has faced international criticism over its protections for millions of migrants from poorer neighbouring countries, and over the plight of stateless Rohingya Muslims trafficked from Myanmar and Bangladesh aboard overcrowded boats. Dozens of graves as well as pens likely used as cages for Rohingya have been found in abandoned jungle camps on both sides of the Thai-Malaysian border.

Kerry is visiting Malaysia for annual security talks between the 10-member regional bloc, the Association of Southeast Asian Nations, and its international partners. Those talks are expected to focus on China's island-building in the disputed South China Sea that has rattled its China's neighbours and strained relations between Washington and Beijing.

Kerry, who starts his travels in the Middle East, will also visit Singapore and Vietnam.

While in Malaysia, the U.S. official said Kerry will steer clear of the domestic political scandal that has embroiled Prime Minister Najib Razak, who denies allegations that some $700 million from a state investment fund went into his personal bank accounts.

Najib recently fired the attorney general who had been investigating him and a deputy who has been among his most prominent critics.