THE warning, bordered in black, was blunt."To the residents of Ramallah and El Bireh," read the hand lettered Arabic text. "Following the recent serious incident in El Bireh, Jewish residents of the area will not be silent. We know what to do. Jewish blood will not be shed in vain." Jewish settlers drove into Ramallah last Monday - a week after local settler Zvi Klein was ambushed and shot to death by Palestinian gunmen in nearby El Bireh - to plaster the threat on walls and scatter it in leaflets. Klein was the third settler in five weeks to be killed by gunfire in the occupied territories, the victim of a rising tide of firearms use by Palestinians since the end of the Gulf war last March. Settlers, alarmed by the trend toward increased violence in the four-year-old intifadah (uprising), are organizing in response, sending out messages such as the one that appeared this week in Ramallah and planning patrols on major roads in the West Bank. Some settlers are also reacting to Palestinian violence in kind. Aharon Domb, a resident of Kiryat Arba settlement near Hebron, opened fire on a group of children who were throwing stones at his car last Monday. Such moves prompted Ehud Barak, chief of staff of the Israeli Defense Forces (IDF), to complain that the settlers appeared to be usurping the role of the Army in maintaining security. "We are responsible for the rule of law in the whole of Judea and Samaria [the West Bank]," he told Israeli television on Tuesday. "Israeli citizens are free to move, and whoever is allowed to carry a weapon is allowed to carry a weapon. But no one is allowed to arrest a suspect or carry out an investigation, or anything like that," he added. The Army, however, is reluctant to condemn openly any resort to violence by the settlers, whose bid to populate the West Bank and Gaza Strip with Jewish residents enjoys the full support of Prime Minister Yitzhak Shamir's Likud government. Settler leaders say they would like to see more soldiers in the territories to deal with the intifadah, and to protect settlers from Palestinian violence. "Whenever there is a hot terrorist attack, naturally there is pressure from Israelis in the territories to increase our military presence," says one Army officer. "But Barak does not want to invest huge resources in that direction at the expense of developing the Army of the future." A gradual reduction in the number of Israeli soldiers deployed in the occupied territories has followed a marked drop this year in the number of classic intifadah incidents, such as the erection of barricades or stoning of Army vehicles. According to Army records, there were 26,835 such clashes between the end of the Gulf war and the end of November, half the number from the same period last year. At the same time, however, the use of more violent methods by a small number of more committed intifadah activists has increased, according to IDF figures. Since the Gulf war ended, Palestinian gunmen have opened fire on Israeli soldiers or settlers 113 times, a 50 percent jump from last year. There have also been 79 hand grenade or Molotov cocktail attacks, as against just eight in the whole of 1990. Rising anger among settlers at this trend seethed into open revolt after an ambush on a settler bus Oct. 28, the eve of the Madrid peace conference, in which two passengers, Rachel Druck and Yitzhak Rofeh, were killed. Activists determined to establish a new Jewish settlement at the site of the attack defied Army orders to remove their caravans until the government eventually gave them permission to join a military outpost. In the wake of Klein's death last week, the settlers announced plans to set up patrols on roads in the West Bank. "If rocks are thrown, and the Army is not there to see it ... we will have cars on the road that will be able to contact the armed forces [by radio] and get them out there faster to deal with the situation," said Yehuda Pinsky, deputy mayor of a cluster of settlements north of Jerusalem. It is unclear whether the recent spate of violence and threats marks the beginning of a sustained and calculated policy on both sides of the battle between settlers and Palestinians. "There are always a few hotheads," says settler spokeswoman Avigail Frij. "But most people are steadfast. Their answer is simply to live here." For radical Palestinian leader Riyad Malki, increased weapons attacks "are not a reaffirmation of the armed struggle as such, but are incidents related to certain events. I do not expect to see a surge in the use of firearms, even if the peace negotiations fail." Other Palestinian figures are not so sanguine. Commenting on an Israeli Cabinet decision to allow Jewish settlers to take over houses in the Palestinian neighborhood of Silwan in East Jerusalem, Faisal al-Husseini warned on Wednesday that "the government is pushing our people to use other means, out of the negotiating table, and this is a dangerous thing." Some 30 settlers, heavily guarded by police, moved into six houses in Silwan before dawn on yesterday, following a decision by the attorney general that their disputed leases on the properties were valid.