Federal funding could be at stake as Common Core testing problems continued in Nevada, Montana and North Dakota, state and U.S. officials said.

The three states contract with New Hampshire-based Measured Progress to administer the tests that are linked to hotly disputed, federally backed education standards.

"We expect states to hold Measured Progress accountable, just like we expect the states to hold the districts accountable" for testing, said Dorie Nolt, a Department of Education spokeswoman.

On Tuesday, the company's server crashed due to capacity, causing spotty access and logistical frustrations before testing stopped. It also cost some schools money in the form of substitute teachers.

The state of Montana offered waivers Wednesday to the mandatory assessment for this year, which could put millions of dollars in federal funding at risk.

"I think it was best for those schools to make that decision for themselves knowing that the assessment is still important," said State Superintendent Denise Juneau.

Most have not announced their decisions, although a small number have already declared that they will not test or will only partially test students. So far, about 20 percent of the state's school districts committed to full testing.

Juneau said she expected most schools to finish the tests but the federal mandate may not be met.

"We don't know — until everyone's done testing — what the participating rate will be, but it will be high," she said.

The U.S. Department of Education said in a statement: "The department has not had to withhold money — yet — over this requirement because states have either complied or have appropriately addressed this with schools or districts that assessed less than 95 percent of students."

North Dakota said it is prepared for any consequences, given that some districts are ending the school year in as few as 20 days.

Officials encouraged finishing the computer test or ordering the paper test. Any school system that can't get it done will document attempts in what could be a plea for leniency later.

"I think the Department of (Education) will look at the effort we give in," said Kirsten Baesler, North Dakota's state superintendent. "Did they give up the second week of April or was it a substantial effort?"

This week's debacle was the second technical problem Measured Progress has had in recent weeks with the computerized English language arts and math tests for selected grades. In March, testing was delayed because of a coding issue.

The company said its servers couldn't handle the number of students even though it increased capacity beyond what was indicated by the tests' creator, Smarter Balanced.

Nevada likely overloaded the system because it has 210,000 of the 345,000 total students expected to take the test across the three states.

The state was put on its own server to do limited testing Thursday, which will continue Friday.

But problems appeared again as early as Thursday morning and led Nevada's largest school system to cancel plans for the day.

"We can't keep putting our kids in front of an error screen," said Leslie Arnold, an assistant superintendent with the Las Vegas-based Clark County School District.

The country's fifth largest school system said it expects all 150,000 kids to complete the test this year.

Meanwhile, Montana's limited testing Thursday was successful and full testing begins again Friday. The state also defended Measure Progress, calling it a victim to the initial coding problems.

North Dakota said it's not clear how it will deal with the company. Its three-year contract started this year and cost $4.68 million.

"When the dust settles and our students are taken care of and the school year concludes, then we'll begin to look at what happened here," Baesler said.