UN secretary-general Ban Ki-moon says the situation in Yemen is a ticking time bomb
The Saudi-led coalition forces trying to repel the Shia Houthi rebels and militia loyal to former President Ali Abdullah Saleh have carried out scores of raids into Yemen since late March.
King Salman bin Abdulaziz al-Sauds zero-tolerance stance on the Houthis stems from his belief that they are acting as a proxy force for Iran and that if Iran is fighting a war on your border, you have to act.
The monarch has said any escalation of violence will be met with equal or greater force, although there is still no sign of ground troops being sent in to tackle the Houthis head on.
Since September 2014, the rebels have enjoyed great success in Yemen and the prospect of exiled President Abd Rabbu Mansour al-Hadi returning to lead the country looks as remote as it has ever been.
As of mid-June, Houthi forces had made serious inroads into new territories close to the Saudi border, aided by militia loyal to Saleh. The rebels now control the capital, Sanaa, as well as several central provinces since forming an alliance with Salehs militia forces.
The dominant position enjoyed by the Houthis will have given them stronger bargaining power for the talks due to take place in Geneva in June.
The negotiations will try to broker a peace deal, although exactly on what terms remains to be seen. UN secretary-general Ban Ki-moon called the situation in Yemen a ticking time bomb in a press conference on 15 June and said that, at the very least, a ceasefire was an essential result.
However, as of 16 June, the Houthi-led delegation of 23 had not yet made it to Geneva and was believed to be in the East African state of Djibouti. Media reports stated they were on a UN-owned plane to Switzerland for talks, but had not yet arrived.
Ban Ki-moon met with Al-Hadis representatives on 15 June, as well as a self-styled Group of 16 countries that are monitoring events in Yemen. However, the late arrival of the Houthi delegation will mean they cannot meet with Ban Ki-moon as he had to leave Geneva.
How successful the UN meetings will be is unknown, but media reports in Saudi Arabia have shown Riyadh will not be satisfied unless Al-Hadi is reinstated. With the Houthis and their allies in such a strong strategic position, it is unlikely they will be willing to welcome back an exiled president. If Al-Hadi is to return, it is more likely he will need to be accompanied by a large number of Saudi-led troops.