North Carolina reported 2,532 new cases on Thursday, representing the state's highest single-day increase since the start of the pandemic. Health officials reported 1,926 new cases the previous day.

"Today, NC reported 2,532 new cases of #COVID19, our highest day of cases. Our trends are headed in the wrong direction, but we can turn this around, just as we have throughout the pandemic," the state's health department tweeted Thursday.

The jump in new cases was accompanied by an increase in completed tests. The percentage of positive tests dropped slightly to 6.5%, but was still well above the September average of about 5%.

At least 311 patients had been admitted to local hospitals with symptoms of COVID-19 over the last day.

Officials in El Paso, Texas, announced new activity restrictions to slow the spread of the virus as new cases and hospitalizations rose to an all-time high.

The city reported 717 new cases and 20 delayed testing results on Thursday, bringing the total number of active cases to 6,887. Health officials also announced an additional death, bringing the total number of fatalities to 554. The patient was described as a male in his 80s with health conditions.

"Today’s spike is part of an overall increase in cases seen over the last week due to community spread believed to be caused by COVID-19 fatigue resulting in residents letting their guard down," city officials tweeted Thursday. "For this reason, the Mayor and City Attorney’s Office are working with the Department of Public Health (DPH) and Office of Emergency Management to further restrict activities in our community to slow the spread. These strong restrictions are necessary and must be enacted."

Officials in Hong Kong and Singapore announced an agreement to establish a bilateral Air Travel Bubble in an effort to revive cross-border air travel between the two aviation hubs.

Citing low incidents of COVID-19 infections and 'robust' anti-transmission mechanisms, Singapore's Transport Minister Ong Ye said it is a "safe, careful but significant step forward to revive air travel, and provide a model for future collaboration with other parts of the world."

Hong Kong and Singapore are both major financial hubs, and the international air route between the two cities was among the busiest in the Asia-Pacific region before the pandemic took shape, officials said in a statement.

They did not offer details about a potential launch date.

-ABC News' Christine Theodorou contributed to this report.

The Biden campaign has announced that two people traveling with Sen. Harris in Arizona, Communications Director Liz Allen, and a non-staff flight crew member, have tested positive for COVID-19

“Senator Harris was not in close contact, as defined by the CDC, with either of these individuals during the two days prior to their positive tests; as such, there is no requirement for quarantine," Jennifer O'Malley Dillon, Biden's campaign manager, said in a statement.

“Neither of these people have had contact with Vice President Biden, Senator Harris or any other staffers since testing positive or in the 48 hours prior to their positive test results," she added.

The campaign is canceling Harris' travel through Sunday "out of an abundance of caution and in line with our campaign's commitment to the highest levels of precaution."

Harris will return to in-person campaigning on Monday.

-ABC News' Molly Nagle contributed to this report.

The national positivity rate for COVID-19 tests across the United States has jumped from 4.7% to 6% in week-to-week comparisons, according to an internal memo from the U.S. Department of Health and Human Services that was obtained by ABC News on Wednesday night.

The memo, which is circulated to the highest levels of the federal government and is used to determine daily priorities for the agencies working on COVID-19 response, said 38 U.S. states and territories are in an upward trajectory of new infections, while four jurisdictions are at a plateau and 14 others are in a downward trend.

There were 359,745 new cases confirmed during the period of Oct. 7-Oct. 13, a 17.1% increase from the previous week. There were also 4,962 fatalities from COVID-19 recorded during the same period, a 2.1% decrease compared with the week prior, according to the memo.

Meanwhile, 24% of hospitals nationwide have more than 80% of beds full in their intensive care units. That figure was 17-18% during the summertime peak, the memo said.

In Arizona, 6.71% of the state's prison population -- 2,599 inmates -- has tested positive for COVID-19, along with 712 prison staff. At least 17 inmates have died from the disease, according to the memo.

The number of new cases recorded in Washington, D.C., increased by 84% over the past week, after dropping to its lowest levels since July. The nation's capital reported an average of 81% of its inpatient beds occupied and 74.2% of intensive care unit beds occupied, the memo said.

Idaho's positivity rate for COVID-19 tests surged to 14.7% for the week ending Oct. 8, twice the national rate during the same period, according to the memo.

Indiana saw a 27.5% week-to-week rise in cases and a 23.4% week-to-week increase in deaths from COVID-19, as of Oct. 11. The state reported three consecutive days of record-high daily case counts from Oct. 8 to Oct. 10. The state's seven-day COVID-19 hospitalization rate reached a five-month peak at 17.3 per 100,000 population on Oct. 11, the memo said.

Minnesota's seven-day COVID-19 hospitalization rate also hit a five-month peak at 11.3 per 100,000 population on Oct.11. Minnesota reported a 19% increase in cases between the weeks ending Oct. 4 and Oct. 11, which state health officials said is linked to widespread transmission rather than clustered outbreaks, according to the memo.

Mississippi saw a 22.4% increase in COVID-19 cases in the week ending Oct. 11, compared to the previous week. The seven-day and 14-day averages for new cases continued to rise statewide, reaching levels not seen since early September. State officials are concerned that Mississippi is at the start of a second surge and have estimated that the cause of the increasing spread is sustained community transmission. Six major hospitals in the state were reported to have no more ICU surge capacity, the memo said.

Meanwhile, COVID-19 has devastated the Mississippi Band of Choctaw Indians, with the disease infecting more than 10% of the tribe and killing at least 81 of them, according to the memo.

North Carolina and Tennessee are two of five U.S. states that reported a greater than 50% increase in COVID-19 cases over the past week, the memo said.

COVID-19 hospitalizations continue to rise across Ohio, with the state's seven-day rate at 11.9 per 100,000 population on Oct. 11, according to the memo.

Pennsylvania recorded its highest daily case count in six months on Oct. 10 with 1,742 new cases. Multiple counties across the state reported a doubling of new cases during the period of Oct. 5-11, the memo said.

ABC News' Josh Margolin contributed to this report.