WASHINGTON — President Barack Obama said Tuesday that the U.S. has offered to help Mexico figure out what happened to 43 college students who have been missing since September, but he stopped short of saying that aid to the U.S. ally and neighbor should be reconsidered on the basis of the country's human rights record.

"We've offered assistance in tracking down exactly what happened, our forensic capabilities, our capacity to get to the bottom of exactly what happened," Obama told Telemundo, the Spanish-language television network, in an interview.

On the question of aid, which was posed by the interviewer, the president said what's more important is helping Mexico build on the progress it has made.

"We've got to make sure that we strengthen the criminal justice system, the investigative capacities," he said. "Mexico is our friend and our neighbor. We want them to thrive."

Obama said the crime against the missing students has "no place in civilized society."

The case has ignited indignation across Mexico and around the world over the fact that the students disappeared at the hands of a corrupt local government and that federal authorities took 10 days to intervene. Some have called for President Enrique Pena Nieto to resign.

Obama said he spoke with Pena Nieto last month when both leaders attended an international economic summit in Australia and that the Mexican president "recognizes the outrageous tragedy this represents."

Mexico's attorney general said 80 people have been arrested so far in the case, including 44 police officers from the cities of Iguala and Cocula and former Iguala Mayor Jose Luis Abarca, who is under investigation for ordering the Sept. 26 attacks. The case also forced the governor of Guerrero state to resign.

So far, one student has been positively identified, confirming what the attorney general told parents in November: that the students were rounded up in a conflict with police and had been killed and incinerated by a local drug gang.

Obama said narco-traffickers taking over entire towns or regions, in some cases, is a "chronic problem" in Mexico.