China’s cabinet-level health policymaker pledged “all necessary support” for Hong Kong to fight an escalating Covid-19 crisis as the city confirmed another record-high 123 Covid-19 infections on Friday, and officials warned that hospital and quarantine facilities were fast reaching capacity.

Another elderly nursing home resident with Covid-19 died, and dozens of senior citizens had to be evacuated from a coronavirus-stricken care centre, while the government was under mounting pressure to plug a loophole exposed by the threat of infections among the crew of six cargo ships quarantined in Hong Kong waters.

The country’s National Health Commission said it would support Hong Kong in its anti-epidemic efforts during a conference call with local health officials, after days of speculation the city’s leader had appealed to the mainland authorities for help.

The commission said it would strengthen the exchange of technology and share its experience of combating Covid-19 with Hong Kong.

Aside from the six vessels, which were quarantined in waters off Lamma Island after each ship reported one Covid-19 patient on board, Hong Kong was grappling with fresh cases in two more institutions for the elderly, and across more government departments and the disciplined services, including police, fire service and Immigration Department.

Dr Chuang Shuk-kwan, head of the Centre for Health Protection’s communicable disease branch, told a daily press briefing that 115 of Friday’s total were local cases, 62 of which were linked to previous infections, while 53 were without a known source.

Eight cases were imported, including seafarers from the Philippines and India, as well as returnees from India and Pakistan. The new cases took the city’s infection tally to 2,372, with about 100 preliminary positive cases pending confirmation. The city saw a previous daily high of 118 new infections on Thursday.

“The trend is still increasing,” Chuang said. “Although this situation reflects those [infections] in the past one or two weeks, it’s still worrying because we are seeing the patients have many social activities, which are difficult to trace and it is difficult to put their close contacts under quarantine.”

She said the city’s laboratories, quarantine sites and hospitals were bursting at the seams and pleaded with the public to stay home, noting that about half of the new cases involved unknown sources, and many of those infected were housewives and the elderly who only went out to shop at markets and eat at restaurants.

Four seamen among the latest cases were not related to the six cargo ships, which have more than 100 mariners on board in total, but Chuang said the work of contact tracing had become more difficult as some people did not give phone numbers that could be contacted, or had already left the city when their tests results were ready.

Seamen are exempt from the mandatory two-week quarantine rule, a loophole the government has been urged to plug.

The latest fatality, the city’s 16th, was a 74-year-old resident of Kong Tai Care for the Aged Centre Limited, where 44 infections have been recorded. The man, who was admitted to United Christian Hospital on July 9 and suffered kidney and liver failure, died at 12.48pm on Friday.

He was the fourth resident from the centre in coronavirus-hit Tsz Wan Shan to have died after being infected with the virus.

The authorities moved 50 people from the Salvation Army Lung Hang Residence for Senior Citizens in Tai Wai to a holiday centre for the elderly for quarantine, after one more resident was confirmed to have the coronavirus and two others tested preliminary positive. A cook and a cleaner at the home were also confirmed earlier.

One employee at Cornwall Elderly’s Home in Tuen Mun and another at Cornwall Elderly’s Home in Tai Po were confirmed with the virus, while a personal carer, who lives in Tsz Wan Shan and had visited two to three families, was also among the cases.

The city’s third wave of Covid-19 has so far led to infections in five care homes for the elderly.

More government departments were also affected. Officials said an officer in the traffic division at New Territories South regional police headquarters, a firefighter in Cheung Chau, and a senior immigration officer – the fifth from the department to be infected – had all caught Covid-19.

The Water Supplies Department said three construction workers of its contractor at Tuen Mun Water Treatment Works tested positive but drinking water safety was not affected.

A Leisure and Cultural Services Department worker responsible for tree management works in Tsuen Wan and Kwai Tsing, and a Registration and Electoral Office worker were confirmed cases, too.

Chuang urged civil servants to refrain from eating together and avoid visiting other departments if online meetings could be held instead.

The Hospital Authority said a patient who had been given red blood cells from a donor later confirmed to be infected with Covid-19 tested negative for the virus.

The government was also forced to clarify on Facebook on Friday afternoon that it had no plans to implement a complete lockdown for seven days next week after fake news circulated on social media platforms. It appealed to the public to access Covid-19 information through credible channels.

Meanwhile, an international team of researchers including University of Hong Kong infectious disease expert Yuen Kwok-yung conducted a large-scale evaluation of nearly 12,000 drugs, and found 13 showed “promising” results at blocking viral replication at clinically used dosages.

Three of the most effective, including one for tackling Ebola, were found to reduce the number of Covid-19 infected cells by a range of 65 to 85 per cent.