Sri Lanka has defaulted on its debt for the first time in its history as the country struggles with its worst financial crisis in more than 70 years, BBC reported.

A 30-day grace period to come up with $78m (£63m) of unpaid debt interest payments expired on Wednesday.

The governor of the South Asian nation's central bank said the country was now in a "pre-emptive default".

Later on Thursday, two of the world's biggest credit rating agencies also said Sri Lanka had defaulted.

Defaults happen when governments are unable to meet some or all of their debt payments to creditors.

It can damage a country's reputation with investors, making it harder for it to borrow the money it needs on international markets, which can further harm confidence in its currency and economy. 

Asked on Thursday whether the country was now in default, central bank governor P Nandalal Weerasinghe said: "Our position is very clear, we said that until they come to the restructure [of our debts], we will not be able to pay. So that's what you call pre-emptive default, according to BBC.

"There can be technical definitions... from their side they can consider it a default. Our position is very clear, until there is a debt restructure, we cannot repay," he added.

Sri Lanka is seeking to restructure debts of more than $50bn it owes to foreign creditors, to make it more manageable to repay. 

The country's economy has been hit hard by the pandemic and rising energy prices, but critics say the current crisis has been of the previous government's own making.

A chronic shortage of foreign currency and soaring inflation have led to a severe shortage of medicines, fuel and other essentials. 

Professor Mick Moore from the University of Sussex and former consultant on Sri Lanka for the Asian Development Bank said even though it looked like Sri Lanka was struggling from the effects of global economic problems, it was "emphatically not that".

"This is the most man-made and voluntary economic crisis of which I know," he told the BBC's Today programme.

Prof Moore said the previous administration had borrowed money for infrastructure projects and then "insisted in this very macho fashion" on repaying mounting the debts, rather than restructuring them with creditors. 

He said the then government "went along in this way until about six months ago and basically they had given away virtually all the foreign exchange they could command".

"This is egregious incompetence," he added.

Prof Moore said the country faced a "very critical situation".

In recent weeks, there have been large, sometimes violent, protests against President Gotabaya Rajapaksa and his family due to the growing crisis.

The country has already started talks with the International Monetary Fund (IMF) over a bailout and needs to renegotiate its debt agreements with creditors, BBC reported.

Later on Thursday, an IMF spokesman said the current talks on a potential loan programme were expected to conclude on Tuesday. 

Sri Lanka's government has said previously that it needs as much as $4bn this year.

Mr Weerasinghe warned that Sri Lanka's already very high rate of inflation was likely to rise further.

"Inflation obviously is around 30%. It will go even [higher], headline inflation will go [up] around 40% in the next couple of months," he said.

He was speaking after Sri Lanka's central bank held its two key interest rates steady following a seven percentage points rise at its last meeting.

The country's main lending rate remained at 14.5%, while the deposit rate was kept at 13.5%, according to BBC reported.