U.S. banned Kenya's attorney general: envoy

Government representatives Sam Ongeri (L), Mutula Kilonzo (2nd L), Martha Karua (2nd R) and Attorney General Amos Wako (R) talk as U.S. Secretary of State Condoleezza Rice meets Kenya's President Mwai Kibaki at Harambee House, the Office of the President, in Nairobi in this February 18, 2008 file photo.

NAIROBI (Reuters) - Kenya's attorney general Amos Wako was the senior government official handed a travel ban by Washington last month, the U.S. envoy to Kenya said on Sunday.

There has been intense speculation in Kenya over who had been banned, with Wako high on most lists given that Washington has criticized him several times for not cracking down on corruption during his 18-year tenure.

Ending a culture of impunity in a country where corruption is almost endemic is seen by international donors has a crucial step toward avoiding a repeat of last year's post-election violence at the next presidential election in 2012.

U.S. Assistant Secretary of State Johnnie Carson announced the travel ban during a visit to Kenya last month and said Washington was considering similar action against three more prominent Kenyans. But he declined to name the official.

Ending the speculation, U.S. ambassador Michael Ranneberger directed readers of his Twitter page to The Standard newspaper, saying: "Still wondering which senior Kenyan official has been banned from the U.S. for obstructing reforms? The answer is:"

The front page of the Standard read: "U.S. ban: It's Wako."

Wako has been criticized for failing to prosecute the perpetrators of the post-election violence that killed at least 1,300 people, and for not nailing the architects of several audacious corruption scams worth hundreds of millions of dollars.

Announcing the ban, Carson said the official in question had been "obstructive in the fight against corruption."

Watchdog Transparency International ranks Kenya as the most corrupt nation in east Africa.

While President Mwai Kibaki has yet to respond to the U.S. ban, Foreign Minister Moses Wetangula said on Wednesday Kenya regretted that Carson had arrived uninvited and then made "fairly unacceptable and reckless statements."

Washington has been one of the most outspoken critics of Kenya's coalition government for slow progress on reforms agreed as part of a deal to end the 2008 violence.

The International Criminal Court (ICC) is also investigating people considered most responsible for funding and fuelling the clashes that followed a disputed presidential election in 2007.

ICC prosecutor Luis Moreno-Ocampo is due to visit in Kenya on Thursday amid growing speculation he may soon take action against a few influential members of the government.

(Editing by Richard Williams)