The government has imposed a lockdown in the southern Sindh province – home to nearly 50 million people and the country’s largest city, Karachi – in a desperate attempt to stem the rising number of coronavirus cases in the country, an official said.

The lockdown starting Sunday midnight will last two weeks in the province, which has reported almost 50% of the total 645 coronavirus cases in Pakistan, Chief Minister for Sindh Syed Murad Ali Shah announced in a video message.

"There will be a lockdown all over the province from today midnight for 15 days," Shah said, urging people to observe self-quarantine and stay off the streets for the next two weeks.

All markets, shopping malls, restaurants, public beaches, and other public spots will remain closed. Public transport will also remain shut, he announced. All schools, colleges, and universities across the province are already closed through May 31.

Also, Islamabad on Saturday suspended all international flights for two weeks.

However, members of the public will be allowed to come out in case of a dire need, particularly medical emergencies. Only one person will be allowed to travel with the driver in private cars in case of urgent need, Shah said.

Prime Minister Imran Khan, for his part, said he opposes a complete lockdown in the country of over 200 million people with a weak public healthcare system, as he believes it next to impossible.

In a televised address to the nation minutes before the lockdown announcement, Khan said as 25% of the country's population lives below the poverty line, their livelihoods would be badly hit by a complete lockdown, which he called tantamount to a curfew.

"It would sow chaos in the country more perilous than coronavirus," he added.

"The only thing that can save us from this pandemic is, stay at home. I’m sure my people will not disappoint me," he said.

The novel coronavirus emerged in Wuhan, China last December, and has spread to at least 163 countries and territories. The World Health Organization declared the outbreak a pandemic.

Out of more than 307,000 confirmed cases, the death toll now exceeds 13,000 and over 92,000 have recovered, according to data compiled by the U.S.-based Johns Hopkins University.

Despite the rising number of cases, most people who contract the virus suffer only mild symptoms before making a recovery.