More girls kidnapped in Nigeria

(CNN) -- Amid news of more Nigerian girls being kidnapped by a militant Islamist group, the country's President said he welcomed an offer of U.S. support in the search for them, the U.S. State Department said Tuesday.

The U.S. Embassy in Abuja, Nigeria, is ready to create a "coordination cell" to provide intelligence, investigations and hostage negotiation expertise, State Department spokeswoman Jen Psaki said. The cell would include U.S. military personnel, she said.

Secretary of State John Kerry called Nigerian President Goodluck Jonathan on Tuesday to reiterate an offer to help, Psaki said. The conversation happened on the same day that CNN and the Reuters news agency confirmed that at least eight more girls had been snatched in Warabe village, which is in the northeastern part of the country.

Warabe residents told CNN that gunmen moved from door to door late Sunday, snatching the girls, who are between 12 and 15 years old.

The latest abductions come amid international outcry over the April 14 kidnapping of hundreds of girls by the organization Boko Haram, which U.S. officials say is trained by al Qaeda affiliates. There has been widespread criticism that the Nigerian government is not doing enough to rescue the girls.

"The President and the government is not taking this as easy as people all over the world think," Doyin Okupe, senior special assistant to Jonathan told CNN's Isha Sesay. "We've done a lot but we are not talking about it. We're not Americans. We're not show people, you know, but it does not mean that we are not doing something."

Specifically, he said two special battalions have been devoted to the search for the missing girls and more troops are on their way.

Okupe said there is a "hot pursuit" on for the kidnappers.

"Certain things have been ordered. Certain things have been put in place, which I am not in position to say now," Okupe said. "I am very, very sure that this time around, you know, the terrorists have made a major error, and we will get them."

Also on Tuesday the United Nations human rights chief blasted Boko Haram and sent a stern warning to the group that under international law, slavery and sexual slavery are "crimes against humanity."

"The girls must be immediately returned, unharmed, to their families," U.N. High Commissioner for Human Rights Navi Pillay said in a news release.

Since Pillay visited Nigeria this year, the statement read, Boko Haram's actions have "grown increasingly monstrous."