The top United Nations peacekeeping official says 500 troops have been deployed to the disputed Abyei region, which is claimed by both Sudan and South Sudan.

Alain Le Roy told the Security Council Wednesday that he expects to have up to 1,200 troops in the region by Sunday.

Le Roy says the situation in oil-rich Abyei remains tense. But he says Sudan and South Sudan both appear committed to avoiding an escalation in violence.

The U.N. has authorized a total deployment of 4,200 troops to the region. The U.N. Security Council created the Interim Security Force for Abyei in June.

In May, the Sudanese army occupied Abyei amid a dispute over the region between Sudan's central government and what was then the country's semi-autonomous south.

South Sudan declared independence on July 9 but the sides have yet to determine who will ultimately control Abyei.

The South Sudan referendum vote to split from the north was part of a 2005 peace agreement. That pact ended a 21-year north-south civil war in which the Abyei region was a key battleground.