DUBAI — A jump in coronavirus cases in Iran is a cause for concern because they have no direct link to China, the World Health Organization said. The outbreak also accelerated in South Korea and Italy. A new study estimated that two-thirds of cases exported from China have gone undetected worldwide.

China adjusted the number of cases for the third time this month, raising more questions over the reliability of the data even as new cases decline. An aviation conference scheduled for May in Hong Kong was canceled.

Alarmed over the increasing number of cases in Iran, Kuwait has launched an airlift to evacuate 900 citizens from there, Kuwaiti media reported Sunday.

The Kuwaitis were repatriated aboard six flights as part of precautions taken by the Gulf country to keep the viral ailment at bay.

Iran now seems isolated with several neighboring countries including Afghanistan, Pakistan, Turkey and Jordan either closing the border with the republic or putting travel ban to and from it.

Both Afghanistan and Pakistan share long, porous borders with Iran that are often used by smugglers and human traffickers, while millions of Afghan refugees currently live in the republic — raising fears that the virus could easily spread over the border.

"To prevent the spread of the novel #coronavirus and protect the public, Afghanistan suspends all passenger movement (air and ground) to and from Iran," the office of the National Security Council of Afghanistan said in a statement posted on Twitter.

A provincial official in Pakistan and the country's Frontier Corps also confirmed that the country had sealed the land border with Iran.

Jordan said it would bar citizens from China, Iran and South Korea from entering the kingdom in a bid to prevent the deadly coronavirus outbreak spreading.

Minister of State for Media Affairs, Amjad Adayleh, said the decision was part of "preemptive measures... following the rise in cases of coronavirus in South Korea, Iran" and China.

Earlier in the day, Iran reported eight deaths from the novel coronavirus, the highest toll of any country outside China, as the supreme leader accused foreign media of trying to use the outbreak to sabotage a general election.

Turkey "temporarily" closed its border with Iran. "We have decided to shut the land border temporarily after an increase in the number of cases in our neighbor Iran," Health Minister Fahrettin Koca told reporters.

The land and railway borders will be closed from Sunday, the minister said.

He said air traffic from Iran into Turkey would also be halted but departures to Iran could continue.

South Korea reported 48 more cases, taking the total number to 204. Neighboring Japan is also seeing outbreaks in several unconnected areas. Singapore reported recoveries outpacing new cases. — Agencies