U.S. Secretary of State John Kerry said the United States will do "everything possible" to free the 276 schoolgirls kidnapped by the Nigerian militant group Boko Haram.
Speaking Thursday in Washington, Kerry said a team of U.S. military advisers is arriving in Nigeria to help with communications, logistics, and intelligence.
"Our inter-agency team is hitting the ground in Nigeria now, and they are going to be working in concert with President Goodluck Jonathan's government to do everything that we possibly can to return these girls to their families and their communities. We are also going to do everything possible to counter the menace of Boko Haram," said Kerry.
At least three other countries have pledged to assist Nigeria in the search. Britain has promised to provide satellite imagery, while France says it will send security agents.
Addressing the World Economic Forum summit Thursday in Abuja, Nigerian President Goodluck Jonathan thanked China, the latest country to promise help in finding the girls.
"The United States of America, the United Kingdom and France have also spoken with me, and have expressed their commitment to help us resolve this crisis in Nigeria. I believe that the kidnapping of these girls will be the beginning of end of terror in Nigeria," said Jonathan.
He said those attending the forum were showing their support for the country and dealing a "major blow" to the terrorists. He said if delegations skipped the event, then militants would have celebrated and "committed more havoc."
Boko Haram's leader has said the group intends to "sell" the girls, who were taken from a school in Nigeria's Borno state on April 14.
Nigerian police have offered a $300,000 reward for information leading to the location and rescue of the students.
Boko Haram is blamed for thousands of deaths since it launched an uprising against the Nigerian government in 2009.
The group has attacked schools, churches, mosques, police stations, and markets while seeking to establish strict Islamic law in Muslim-majority northern Nigeria.
Nigeria declared a state of emergency in three northeastern states a year ago but efforts by the military to crush or contain the insurgency have been unsuccessful.