The U.N. refugee agency says it is very concerned over escalating violence in eastern Chad. The UNHCR says the increase in violence is probably linked to the attack on the Sudanese capital Khartoum last weekend by rebels from Darfur. Lisa Schlein reports for VOA from UNHCR headquarters in Geneva.

The U.N. refugee agency says attacks on gendarmes, or armed policemen, and vehicle hijackings are on the rise. On Wednesday, it says two armed officers who provide security to Sudanese refugees in Touloum camp were attacked and killed by three armed men. The attack took place just three kilometers from the camp.

Furthermore, it says two other police officers were severely wounded in the incident. UNHCR Spokeswoman, Jennifer Pagonis says one of the attackers also was killed and another badly injured. She says the attackers, who were local Chadians, were arrested by police.

"Wednesday's fatal attack followed two hijacking incidents on Tuesday," she said. "Near Touloum camp again, three armed men hijacked a vehicle belonging to one of our implementing partners and then drove it to Am Nabak camp about 45 kilometers south of Iriba where they hijacked a vehicle belonging to a local NGO. Gendarmes from Touloum gave chase and the hijackers finally abandoned the vehicles and escaped."

The UNHCR manages 12 camps hosting some 240,000 refugees who fled to Chad from Sudan's Darfur region. The war between Sudanese-backed Janjaweed militia and rebel groups has dragged on for five years.

International experts estimate some 200,000 people have died and 2.5 million people have been made homeless.

Last weekend, rebels from the Justice and Equality Movement, based in Darfur, attacked the Sudanese capital Khartoum. They were eventually routed. But, Sudan blamed neighboring Chad for backing the rebel attack and broke diplomatic relations with the country.

Jennifer Pagonis says the attack has created a very worrisome situation for the refugees and internally displaced people in Chad, as well as for the humanitarian workers who care for them.

"We also fear that the attack on the Sudanese capital Khartoum last weekend could further destabilize the security situation in the east and we have reduced our activities and staff movements as a precautionary measure ...The attack on Khartoum has triggered this precautionary measure by UNHCR so we will be carrying out only essential tasks such as following up on protection cases, food and water distribution and health assistance," she said.

Pagonis says last Sunday, an Antonov plane, which is normally used by Sudan, was seen flying over Oure Cassoni refugee camp near Bahai, scaring the refugees. She says the camp hosts 28,000 refugees and is located just six kilometers from the volatile Chad-Sudan border.