Cyberattackers believed to have been working from China broke through defenses of the US weather service recently, according to a Washington Post report.

US media outlets on Wednesday said that the US National Oceanic and Atmospheric Administration (NOAA) confirmed that some of its websites had been compromised but declined to discuss who may have been responsible.

NOAA, which includes the National Weather Service, reportedly sealed off weather data relied upon for aviation, shipping, and more after security teams caught on to the breach.

Cyberattacks were "deflected," and some NOAA services were taken down temporarily for what was described at the time as "unscheduled maintenance," according to media reports.

The Washington Post quoted US Representative Frank Wolf of Virginia, a Republican, as saying that the NOAA told him "it was a hack and it was China."

The report came just two days after the US Postal Service said hackers stole sensitive personal information from its employees in a large data breach this year, and got some customer data as well.

The postal service said it "recently learned of a cybersecurity intrusion into some of our information systems" and was cooperating with law enforcement agencies in an investigation.

It said the hackers appeared to have accessed "identifiable information about employees, including names, dates of birth, social security numbers, addresses, beginning and end dates of employment, emergency contact information and other information."

A USPS spokesman said the breach affected as many as 800,000 people who are paid by the agency, including employees and private contractors.

The statement said hackers also penetrated payment systems at post offices and online where customers pay for services.

It said the customer data included "names, addresses, telephone numbers, email addresses and other information" but that there was "no evidence that any customer credit card information from retail or online purchases" had been compromised.

The Washington Post, citing unnamed sources, said Chinese hackers were suspected in the breach.

The news comes with US President Barack Obama in China for high-level talks, amid heightened concerns about cyberattacks allegedly from China.