Palestinian Authority President Mahmoud Abbas has launched a scathing attack on armed groups that are firing rockets from the Gaza Strip, saying Wednesday they were responsible for bringing death and destruction to the Palestinians. Addressing thousands of demonstrators outside his office in Ramallah, Abbas said, "So far we have about 250 martyrs in the Gaza Strip and thousands of wounded people and destroyed houses. Why? What are the reasons for this? Let's start searching for the reason for all this." Abbas was referring to the number of Palestinians who have been killed in the Gaza Strip since the kidnapping of Cpl. Gilad Shalit in June. His comments, which were interpreted as criticism of Hamas and its government, came hours before Abbas headed to the Strip for talks with PA Prime Minister Ismail Haniyeh on forming a national-unity government. Abbas described the rockets that are being fired into Israel as "pipes" that provided Israel with an excuse to carry out military operations in the Gaza Strip. "Our people don't deserve these tragedies," he said. "If these pipes provide an excuse, it's time to stop using them." Last week, Abbas's Fatah party, after three days of discussions in Jordan, authorized him to open negotiations with Hamas and other Palestinian factions. It's not clear how long Abbas will stay in Gaza, but one of his aides told The Jerusalem Post that he was "very serious" about striking a deal with Hamas as soon as possible. "The negotiations with Hamas could take one day or one month, but this time the president is determined to reach an agreement on the national-unity government because of the deteriorating situation in the West Bank and the Gaza Strip," the aide said. "The financial and security deterioration cannot continue for long and the pressure from the people is growing." Abbas told the demonstrators, who came to demand their salaries, he supported the establishment of a national-unity government because it would convince the international community to resume financial aid to the PA. "We will continue with our efforts to achieve national unity," he said. "We want a government that would be able to bring us money." Earlier, Abbas met with UN Secretary-General Kofi Annan and urged him to get Israel to halt military operations in PA-ruled areas and to release Palestinian prisoners. Abbas also called for an end to the construction of settlements and the security fence in the West Bank. Abbas told reports he had briefed Annan on his efforts to establish a national-unity government and to secure the release of Shalit. "Military force and the continued occupation of Palestinian lands won't bring peace," he said. "Security and stability will be achieved only if the legitimate rights of the Palestinians are achieved." Annan said after the meeting that the IDF had killed more than 200 Palestinians since the end of June, adding that this "must stop immediately." He said he fully agreed with Abbas that "the end of occupation and the creation of a Palestinian state living side by side with Israel is the key to resolving all the problems of the region. We have to implement all Security Council resolutions and that includes, of course, Resolutions 242 and 338." Annan said he had also discussed efforts to release Shalit and to end rocket attacks with Abbas. He called on Israel to reopen the main crossing points to the Gaza Strip. "Beyond preserving life, we have to sustain life. The closure of Gaza must be lifted [and] the crossing points must be opened, not just to allow goods but to allow Palestinian exports out as well," he said. Annan also voiced support for a PA unity government. "If the Palestinians can unite around a common and realistic program, and if this can help bring the security situation under control, it would be a very positive step, and the UN would want to do what it could to support this," he said. "I fervently support all efforts to allow Palestinians to achieve this dream and to live in peace and dignity. They deserve nothing less."