NAIROBI, Kenya (AP) — Kenya's attorney general said Wednesday he is seeking legal advice about whether he can sue the U.S. government for revoking his travel visa.

Attorney General Amos Wako told journalists that he received the U.S. notification Wednesday. He said one of the reasons given for the ban was his alleged involvement "in corrupt actions which have adversely affected the national interests of the United States."

Wako said, "In view of the reasons given, which are defamatory, it is my intention to seek legal advice with a view of instituting legal proceedings."

He is Kenya's longest-serving attorney general. In his 18-year tenure, Kenya has seen huge corruption scandals and repeated political violence, incidents that Wako has been accused by government inquiries of not aggressively prosecuting.

Last week, the top U.S. diplomat for Africa, Johnnie Carson, announced the visa ban but said the official, who was not named at the time, had not been informed because the paperwork hadn't been completed. Carson said three other officials may face similar travel bans.

Carson said the U.S. was taking such actions because the official, who the U.S. State Department later identified as Wako, had been an obstacle to reforms aimed at preventing a repeat of political violence in Kenya in 2007 that saw more than 1,000 people killed. The State Department said Wako's ban was permanent.

Wako defended himself Wednesday, saying he has been active in pursuing reforms. As an example, he cited his work in a government task force on police reform that submitted its report Tuesday.

He also said he had done all he could to prosecute strong cases against high-level officials accused of corruption, adding that where necessary he has sought U.S. help but found it insufficient.

"This is clearly a case of double standards where the bigger and competent brother is demanding more from the younger brother, more than he, the bigger brother, can deliver," said Wako.

In September, Carson wrote warning letters to 15 Kenyan ministers and other prominent figures, saying the U.S. was reviewing its relationship with them but did not say whether they would face sanctions.

(This version CORRECTS SUBS graf 10 to correct quote; EDITS to CONFORM)