By Louis Charbonneau

UNITED NATIONS (Reuters) - U.N. Secretary-General Ban Ki-moon wants to send more peacekeepers to protect an oil-rich region on the border of north and south Sudan where violent clashes broke out earlier this year.

The recommendation to deploy two more companies of troops to the Abyei region, including an armored personnel carrier platoon, was in Ban's latest report to the Security Council on Sudan's north-south armistice circulated at the United Nations on Tuesday.

The call for more peacekeepers known as UNMIS in Abyei, which straddles the border between northern and semi-autonomous southern Sudan, came after an investigation of the actions of UNMIS troops during an attack in May that killed dozens of people and forced about 50,000 from their homes.

The top U.S. envoy to Sudan, Richard Williamson, had accused UNMIS of hiding in their barracks instead of protecting Sudanese civilians in line with their mandate.

The clashes between northern and southern troops ignited fears at the time that a new civil war could erupt.

Ban's report identified two other potential flashpoints where additional troops should be deployed -- the southern Blue Nile city of Damazin and the capital of southern Sudan Juba.

The reinforcements will raise overall UNMIS troop levels by 600 to 9,975, just under the mandate's ceiling of 10,000.

Williamson welcomed the decision to deploy more troops in Abyei and other flashpoints, saying it was an issue he had raised with the new U.N. peacekeeping chief, Alain Le Roy.

"It is absolutely in the right direction," he said.

Williamson said there were too few armed and active UNMIS troops in Abyei at the time of the fighting in the spring -- around 90 out of the full deployment of some 300.

UNMIS has rejected Williamson's criticism of what it did during the fighting, saying it had neither the manpower nor the mandate to intervene militarily.

PRAISE SOFTENED

The final version of the report had significant changes in the section on the U.N. investigation of UNMIS behavior compared with an earlier draft, a copy of which was obtained by Reuters.

That section of the draft, which Security Council diplomats said had come from UNMIS, originally said a U.N. peacekeeping department fact-finding team had "concluded that UNMIS had been unfairly criticized for its response to the crisis."

That was deleted from the final report, as were sections saying that UNMIS "did a good job" during the incident and that "much of the criticism was politically motivated, not least by actors eager to divert attention from their own actions."

The final version said the investigators felt UNMIS "had been successful in protecting a large group of persons inside its compound" but found "room for improvement."

Williamson dismissed the suggestion that his criticism of UNMIS had been politically motivated.

"It had nothing to do with politics," he said. "It had to do with the people that suffered."

UNMIS was established in 2005 to ensure that northern and southern Sudan comply with a peace agreement they signed in the same year that ended two decades of civil war.