Secretary-General Kofi Annan sent letters to Israel and Lebanon spelling out terms for the cessation of hostilities that warn both sides against occupying additional territory or changing the number and location of troops. A copy of the letter to Prime Minister Ehud Olmert, obtained Monday by The Associated Press, set out the UN's expectations of how both sides will fulfill their obligations under the Security Council resolution adopted Friday. A similar letter was sent to Lebanese Prime Minister Fuad Saniora, UN spokesman Stephane Dujarric said. The resolution called for an end to the war between Israel and Hizbullah that has claimed over 900 lives, and authorized up to 15,000 UN peacekeepers to help 15,000 Lebanese troops take control of south Lebanon, which was under Hizbullah's control, as Israel withdraws. The cessation of hostilities took effect at 0500 GMT (0100 EDT) Monday, the 34th day of fighting. Annan told Olmert and Saniora in letters sent Sunday that it "sets out our expectations of how all concerned will fulfill their obligations with respect to the cessation of hostilities." He asked the two leaders to designate a general who would be accessible to the commander of UNIFIL, French Maj. Gen. Alain Pellegrini. He said the three generals should meet within 72 hours of the cessation of hostilities "to discuss arrangements and timelines" for the deployment of UN and Lebanese forces and the withdrawal of IDF troops. That meeting took place Monday morning - just hours after the cessation of hostilities began - at the UN position on the border crossing on the Mediterranean coast at Ras Naqoura. "UNIFIL said the meeting was open and productive and has welcomed it as a positive and encouraging development, and a follow-up meeting is planned for later this week," Dujarric said. In the letter's guidelines, Annan told Israel and Lebanon that once the cessation of hostilities took effect there must be no firing from the ground, sea or air into the other side's territory or at its forces. Neither side can occupy - or seek to occupy - any additional territory from the other side, he said. In order to enable the UN force to monitor compliance with the resolution, Annan said "each side will immediately inform the UN of the disposition of its forces and the territory held by them" when the cessation of hostilities took effect. Israel and Lebanon must also immediately inform the UN "of its information or assessment of the other sides' disposition of forces and territory held by them within the area," he said. Annan also said each side must refrain "from any changes in the strength, composition or disposition of its forces...unless it notified the UN in advance and the UN in turn is able to inform the other side." Annan added that Lebanon and Israel must immediately inform the United Nations if it has been fired on, with as much detail as possible, "refraining from responding except where clearly required in immediate self-defense." Under the UN resolution, Hizbullah is required to immediately stop all attacks but Israel is only required to immediately stop "all offensive military operations." In the case of any firing, Annan said in the letter that "the UN undertakes to bring, in an impartial manner, such incidents to the attention of the Security Council as quickly as possible." Israel and Lebanon were also asked by Annan to designate a general "who is guaranteed to be immediately available to the UN force commander at all times" through a variety of "hotlines" to discuss compliance and to ensure that UN peacekeepers can carry out their job. The secretary-general also asked Israel and Lebanon to designate generals to meet with the UN force commander to discuss "time-lines and modalities for implementing provisions related to any withdrawal or forward deployment of their respective armed forces within the area in question." This should include "certification that there are no unexploded ordinance, mines or booby-traps in the area from which they have withdrawn," he said.