Thailand has seen its highest number of daily Covid cases, with the majority of the new infections stemming from the country's overcrowded prisons.

Some 6,853 prisoners make up for 9,635 of Monday's new cases - more than double the previous daily record.

Thailand admitted there were growing clusters in jails after several prominent activists tested positive.

The country has managed to keep coronavirus numbers low for the last year, but saw a huge spike last month.

A total of 111,082 cases have been reported since the beginning of the pandemic. The previous highest daily total was 4,887 on 13 May, according to Johns Hopkins University.

It also reported 25 new deaths on Monday, bringing the total number of fatalities to 614.

"Many people warned the Thai authorities that they needed to act proactively to avoid such a situation, but it seems they got caught sleeping at the switch," said Human Rights Watch's Asia director in a statement released earlier this month.

How many inmates are infected?

According to the Thai government, almost half of those tested across eight prisons were found to have Covid-19 - 10,748 out of 24,537 inmates.

In the worst-hit prison, in the northern province of Chiang Mai, some 61% of inmates tested positive.

But a Corrections Department official told reporters at a press conference on Monday that not much could be done "in reality".

"Even though there's a command from the Corrections Department director-general for everyone to wear a mask 24 hours a day, in reality it can't be done because (inmates) would have to take a shower and eat. Some are taken out to courts and have to eat there. No one can eat with their mask on," said deputy director-general Dr Veerakit Harnparipan.

"What has happened is something beyond the Corrections Department's capacity because we can't turn down new inmates," Dr. Veerakit added.

However, the Corrections Department added that 12,000 vaccine doses had been secured for inmates and they were trying to procure more. The quarantine period for new prisoners has now been increased to 21 days and testing has been ramped up.

Just last week, most of the country's cases had stemmed from just two prisons outside the capital Bangkok. The Ministry of Justice had said then that these two prisons had to constantly accept new inmates.

According to a report by news agency AFP, only 10 cases were reported in Bangkok Remand Prison on 25 April. This figure jumped to 1,960 last week.

What are conditions like in Thailand's prisons?

Human Rights Watch says there are some 380,000 inmates in Thailand's 143 prisons, adding that there were all "at grave risk from Covid-19 outbreaks".

It called on Thai authorities to "ensure prisoners and detainees have access to adequate protective measures", as well as to "swiftly reduce overcrowding by releasing people who do not pose a serious and concrete risk to others."

However, Thai authorities said the number of inmates had been reduced to 310,000 due to overcrowding alleviation policies.

What is the virus situation in Thailand?

The latest outbreak comes days after Thailand announced plans to allow restaurants to resume dine-in services in Bangkok, though an official added that this would be capped at 25%. However, entertainment venues still remain closed and malls nationwide close at 21:00 local time.

Thailand has so far administered 2.2 million vaccine doses to frontline workers and those in at-risk groups.

Before the current outbreak largely appeared to have kept Covid-19 in check, recording a low death toll for a nation of 70 million people that shares porous borders with four countries, including Myanmar.