London, October 17 (RHC)-- The United States, Britain and the UN special envoy for Yemen have urged the warring sides to the conflict in Yemen to declare an immediate ceasefire.  U.S. Secretary of State John Kerry said after high-level diplomatic talks in London on Sunday that if Yemen's opposing sides accepted the ceasefire, the UN special envoy, Ismail Ould Cheikh Ahmed, would work out some sort of a deal. 

"This is the time to implement a ceasefire unconditionally and then move to the negotiating table," Kerry said after meeting with UK Foreign Secretary Boris Johnson and other officials in London, adding, "We cannot emphasize enough today the urgency of ending the violence in Yemen." 

Kerry also said there was an urgency to implement a ceasefire "as rapidly as possible, meaning Monday, Tuesday."  The top U.S. diplomat also stated that the conflict in Yemen had generated a humanitarian and health crisis. 

Meanwhile, the British foreign secretary said the conflict in Yemen was "causing increasing international concern; the fatalities that we're seeing there are unacceptable."  Boris Johnson said: "There should be a ceasefire and the UN should lead the way in calling for that ceasefire." 

There have already been several attempts to halt the deadly Saudi aggression against Yemen, but such efforts have been stymied.  The Saudi campaign has come under heavy criticism since an airstrike last week on a funeral in the Yemeni capital Sana'a killed at least 140 people. 

The U.S. military provides aerial refueling to Saudi bombers conducting airstrikes on Yemen. Washington has also been providing logistic and surveillance support to the kingdom in the bloody campaign.  Saudi Arabia has admitted that it carried out the airstrike based on what it called bad information.