NAIROBI — More than 1,400 civilians were deliberately killed this year in eastern Congo during two successive military operations, and the United Nations urgently needs “a new approach to protect civilians,” according to a Human Rights Watch report to be released Monday.

The report, based on months of research and more than 600 interviews, paints a bleak and brutal picture of eastern Congo, which has been ravaged by civil war for more than a decade. The presence of about 19,000 United Nations peacekeepers has not seemed able to stop the slaughter.

Among the atrocities listed by Human Rights Watch researchers were cases of girls being summarily killed after being raped, and other victims being tied together before their throats were slit.

The 183-page report also said: “Government representatives said the operations would bring peace and security to the region. They have not.” It called the attacks against civilians “vicious and widespread.”