The United States has banned a senior Kenyan government official from visiting the country and may slap similar travel bans on three more people, US Assistant Secretary of State Johnnie Carson said on Monday.

Carson sent letters to 15 prominent Kenyans in September, threatening them with travel bans for blocking political reforms agreed after last year's post-election violence that killed at least 1,300 people.

The move sparked a bitter row between the United States and Kenya. President Kibaki sent a protest note to US President Barack Obama and the spat was cited as one factor weighing on the Kenyan shilling.

"The U.S. government has taken the decision to revoke the visa of a senior Kenyan government official who has been obstructive in the fight against corruption," said Carson.

He declined to name the person, telling reporters just that he was a senior government official "of influence".

"We are considering similar action with three other government officials," said Carson.

"We will not do business as usual with those who do not support reforms ... those who support violence," he said.

—Reuters