In a statement, Reuters' editor-in-chief Stephen Adler said the organization regretted the decision and stands by Richters' reporting.
"We will continue to provide comprehensive and unbiased coverage from the country," Adler said.
Bahrain has been rocked by waves of unrest as its largely Shiite populace demands greater freedoms and equal rights from tiny island nation's Sunni rulers. But the royal family has come down hard, crushing demonstrators with the help of Gulf forces led by neighboring Saudi Arabia.
Journalists there have come under intense pressure as well, according to the Committee to Protect Journalist's Mohamed Abdel Dayem.
In a telephone interview, he detailed a series of attacks on journalists which he said "all amount to the same thing, which is clearing international journalists out of the country, or restricting their activities to the point where they can't cover the news."
He said the number of detained journalists was uncertain but put it in the double digits, adding that two members of the media -- Karim Fakhrawi, the founder of the opposition daily al-Wasat, and Zakariya Rashid Hassan al-Ashiri, a blogger -- have died in what Abdel Dayem called suspicious circumstances.
The Associated Press does not have a foreign national accredited as a journalist in Bahrain -- it uses Bahrainis to assist with its coverage there.