JERUSALEM, AUG. 19 -- Two Jordanian army soldiers crossed into Israel this morning and clashed with an Israeli army patrol, which killed one of the Jordanians and captured the other, officials said.

The clash heightened tensions between Israel and Jordan at a time when the militaries of both countries are on alert because of the regional crisis sparked by Iraq's Aug. 2 invasion of Kuwait, and both Israel and Jordan suspect the other of preparing for war.

Although the Jordanian soldiers appeared to be acting independently, Israeli officials claimed that the incident, in which no Israelis were reported injured, bolstered their argument that the Jordanian regime of King Hussein is in danger of losing political control.

"Jordan is doing all kinds of things that can't be explained," said an Israeli government official, reiterating a message that senior Israeli officials have been stressing in recent days. "We feel we can no longer trust King Hussein."

Israeli officials are alarmed not only by Hussein's qualified support for Iraqi President Saddam Hussein, but by his tolerance of widespread popular enthusiasm for the Iraqi cause. The Israelis say up to 80,000 Jordanians have volunteered for a "popular army" to fight alongside Iraq's, and claim that the Jordanian army has begun preparations to train and arm the volunteers.

Israel has said publicly that it will take military action if Iraqi forces move into Jordan, and a senior military official told Western journalists last week that the army believes that Hussein "is blowing the winds of war."

Jordan fears that Israel is looking for an excuse to turn Jordan into a battlefield and perhaps push Palestinians living in the occupied West Bank across the border. The king has said he will resist any attempt by foreign forces to move across Jordanian territory.

Official sources said today that Israel had recently conveyed private assurances to Hussein that it has no intention of attacking Jordan and wishes the king to remain in power.

Israeli Defense Minister Moshe Arens also has stressed that Israel will not participate in any blockade of the Jordanian port of Aqaba, which stands less than a mile away from the Israeli port of Eilat. The United States has led an international trade embargo against Iraq, and President Bush has said all ports that could be used by Iraq will be blockaded.

Border incidents are not uncommon between Israel and Jordan, although none had been recorded in the last several months until today. According to Israeli sources, a Jordanian soldier was captured in April trying to cross the border, and there were at least five incidents last year in which Jordanian soldiers crossed into Israel or fired across the border.

The incident this morning took place in an area south of the Damiya, or Adams Bridge, between the West Bank and Jordan. According to the Israeli army's account, a routine patrol traveling along the border discovered the footprints of two infiltrators on the swept track inside the border fence.

The Israeli patrol sighted two men in Jordanian army uniforms about six-tenths of a mile west of the border and ordered them to stop, an army statement said. The Jordanians opened fire on the patrol and a clash ensued in which one infiltrator was killed and the other was slightly wounded and captured, it said.