esday's twin bombings in Jos left at least 118 dead, and four other people were killed in a suicide car bombing in northern Kano.
"These vicious attacks on defenseless Nigerian civilians and Boko Haram's abduction last month of more than 200 girls in Chibok are unconscionable, terrorist acts demanding accountability and justice," State Department spokeswoman Jen Psaki said.
"We continue to stand with the Nigerian government and people in their efforts to defeat violent extremism in a manner that protects civilians and ensures respect for human rights," she added in a statement.
Rescue workers on Wednesday were combing through the rubble of Nigeria's deadliest bomb attack in the central city of Jos, with the Islamic militant group Boko Haram blamed for the atrocity.
It was the latest affront to the Nigerian government's internationally-backed security crackdown in the wake of the mass abduction of more than 200 schoolgirls on April 14 which has sparked a global outcry.
A team of US experts has been in Nigeria since early May aiding the hunt for the missing girls, although so far little progress seems to have been made in finding them.
Undersecretary of state for civilian security, Sarah Sewall, told lawmakers that while it was a "complicated" situation she did believe that the government of Nigeria was capable of fighting Boko Haram effectively.
"I think that with the appropriate political redirection, as well as the concerted effort on the part of specific capabilities, that... the government of Nigeria, can make significant progress in defeating Boko Haram," Sewall told the House Foreign Affairs committee.
"Completely eliminating -- I would hedge on that; the timeframe, I would hedge on that. But I don't think there's any question that the government of Nigeria both can and will" defeat them.
Psaki added US officials "don't think it's too late" to take action "given that the atrocities by Boko Haram are ongoing."
The US was "continuing to lend our unique assets and capabilities to assist in this search and we'll continue to evaluate what additional resources we might bring to bear in support of this effort," she told reporters.