It also asked patients with pre-booked GP appointments to "please bring with you any medications, letters or paperwork you already have". By afternoon on the US East Coast, new infections had fallen to the low hundreds of machines and continue to decline, Avast said.
OXFORD hospitals are "remaining vigilant" after the cyber attack hit the NHS and businesses across the world.
Riverbank IT Management managing director Malcolm Newdick said: "Last week's ransomware attack was the most unsafe malware attack we have seen".
The cyber attack affected many NHS facilities that use a 15-year-old operating system for its virtual infrastructure, which likely contributed to its vulnerability.
Russian cellular phone operators Megafon and MTS said some of their computers were hit and the Russian national railway system said although it was attacked, rail operations were unaffected.
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Wallace denied that underinvestment in the NHS - a key claim of the opposition Labour Party ahead of the June 8 election - may have left health services exposed to such attacks.
NHS Digital said health trusts across England were sent details of an IT security patch that would have protected them from the attack.
Experts are still trying to determine who launched the ransomware attack.
The Twitter account @actual_ransom says that as of 2 p.m. Monday, the hackers behind WannaCry had made just over $55,000.
Earlier, Health Secretary Jeremy Hunt confirmed there had not been a second wave of attacks on NHS trusts and said it was "encouraging" that the level of criminal activity was at "the lower end of the range" anticipated.
"They have been working I know through the night nearly to make sure patches are in place to make sure that hopefully the NHS services can get back to normal", he told BBC radio. However, officials said the spread was starting to slow.
Lieu, who noted on his Web site that he is "one of only four computer science majors serving in Congress", supports changing the vulnerabilities equities process (VEP) to ensure greater transparency in how the federal government notifies software companies about bugs it identifies. Because numerous computers impacted run older Windows systems like XP, Microsoft issued a rare patch for XP, which it had stopped updating more than three years ago.
Ten surgeries across the region were hit by the malware attack, which affected how staff could access patient records. Additionally, experts warn that copycats could also try another attack.