AMMAN, Jordan (AP) — A Jordanian army spokesman says border patrols have shot and killed a gunman who opened fire at them as he and three others tried to cross in from Syria.

The spokesman says the other three were wounded in the Monday dawn exchange.

He declined to disclose their identities.

It is the second clash on the Syrian border since Saturday, when Jordanian patrols returned fire at 10 gunmen in an isolated area, wounding seven and arresting three, according to officials.

A key U.S. Arab ally that has a peace treaty with Israel, Jordan is concerned that al-Qaida or militants affiliated with its rival, the Shiite Lebanese Hezbollah, may target it.

The spokesman insisted on anonymity, saying he is not allowed to comment on an ongoing investigation.