The UN Security Council expressed \"grave concern\" on the deteriorating security and humanitarian situation in Yemen, the Council\'s president Nelson Messone said here on Friday. The Council urged all parties to show \"maximum restraint\" and to \"engage in an inclusive political dialogue,\" Messone, the permanent representative of Gabon who holds the Council\'s monthly rotating presidency, said after the Council heard a briefing from the UN\'s Special Advisor on Yemen Jamal Benomar. Messone said the Council welcomed the ongoing mediation efforts of the Gulf Cooperation Council to help the parties find an agreement on a way forward. The UN High Commissioner for Human Rights will go on a mission to Yemen from June 27 to July 6 to assess its human rights situation after hundreds of persons have died this year during clashes between government forces and protesters. Yemen is one of many countries across North Africa and the Middle East where demonstrators have taken to the streets in large numbers this year to call for greater democracy and freedom.