In April Lee Myung-bak, the South Korean president, agreed to lift a ban on US beef imposed in 2003 after a single case of BSE was detected in the US.

 

Critics accused the president of bowing to US pressure in order to win a free trade deal and protesters have been demanding that the beef deal be either scrapped or renegotiated.

 

There have also been growing calls for Lee to resign.

 

Last week the entire South Korean cabinet offered to quit, in an apparent effort to calm public anger, but protests have continued.

 

Commenting on the failure of the Washington talks to resolve the crisis, South Korea's foreign ministry said both sides had "agreed to co-operate to produce a mutually satisfactory resolution".

 

'Diplomatic channels'

 

South Koreans angry at the beef deal have
taken the protests to the White House [EPA]
It said talks would continue "through diplomatic channels".

 

Despite the agreement in April, the tide of protests in South Korea mean that imports of US beef have yet to resume.

 

South Korean negotiators have been hoping to persuade US exporters to agree to send only beef from cattle younger than 30 months, which are considered less susceptible to BSE.

 

Such safeguards were not part of the original April agreement and US trade officials have been reluctant to agree to a formal renegotiation of the deal.

 

On Sunday Lee said he hoped to get agreement on a voluntary arrangement with US exporters to restrict shipments only to younger beef.

 

The beef row has escalated into a major political crisis for the South Korean president, less than four months after he took office.

 

Lee was elected to the presidency last December after winning the biggest political landslide in South Korean election history, but his popularity has plummeted in recent weeks.

 

In addition to the beef dispute, he is also grappling with domestic anger over rising fuel prices which last week triggered a strike by one of South Korea's biggest lorry drivers' unions.