WASHINGTON, July 23 (Xinhua) -- The United States on Wednesday condemns the twin bombings in Nigeria, which have killed more than 70 people.

The United States deplores the attack targeting Shaykh Dahiru Usman Bauchi, one of the Nigeria's most respected Muslim scholars, State Department spokeswoman Marie Harf said in a statement.

Two bomb blasts rocked Nigeria's northern state of Kaduna, killing more than 70 persons and security sources, eyewitness said on Wednesday. Shehu Umar, the state police commissioner, put the official death toll at 39.

The United States is also concerned about reports that these blasts may have also targeted former head of state General Muhammadu Buhari, Harf said.

"We call on Nigerian authorities to fully investigate these attacks," Harf said.

The United States also urges all Nigerians to avoid reprisals and continue to practice the interfaith cooperation that violent extremists seek to undermine, the spokeswoman added.