Two Israelis were killed yesterday at the Karni Terminal between Israel and the Gaza Strip, while an IDF officer was killed in Nablus earlier in the day during an exchange of gunfire with wanted Palestinians.

Lt. Daniel Mandel, 24, was killed, and two soldiers in his Nahal unit were injured, one seriously, in an early-morning operation to arrest wanted men in Nablus. Mandel, a resident of Alon Shevut, was buried yesterday afternoon in Kfar Etzion.

Later in the day, a Palestinian gunman entered the Karni Terminal, where goods are moved between Israel and Gaza, hurling hand grenades and spraying automatic weapon fire, killing Zachar Chanukayev, a 39-year-old fork-lift driver at the terminal from Sderot, and Ahmed Kara, 20, a truck driver from Shuafat, near Jerusalem. Seven other Israelis also were injured in the attack.

The gunman, Mohammed Yunis, an 18-year-old from the Jabaliyah refugee camp, was killed by troops at the scene.

Hamas claimed responsibility for the attack, calling it an act of revenge for Israel's killing one of its top commanders, Sa'ad al-Arbeed, along with six other Palestinians in Gaza City last week.

Thousands of police and security services personnel are to be on high alert across the country starting today and throughout the Pesach holiday. There have been at least 55 alerts about Palestinian plots to strike at Israelis during the week, according to defense sources, prompting Defense Minister Shaul Mofaz to declare last night a general closure in the territories starting today.

As a result of yesterday's Karni Terminal attack, Transportation Minister Avigdor Lieberman ordered the area closed, effectively shutting off Gazan imports and exports. A ministry spokesman said the minister is aware of the terminal's importance to Gazans, and its closure was meant to "teach them a lesson."

"Karni is the artery of life for Gaza," said Lt. Col. Adi Ashkenazi, head of economic cooperation for the IDF's coordination and liaison office with Gaza. "It's not that Gaza can't function for a few days with Karni closed, but there's no doubt that what happened yesterday was an enormous blow to Palestinian interests. It hurts their ability to meet commercial commitments, and there are products that won't last, like fruits and vegetables."

Until 18 months ago, Palestinian Authority officers worked at the terminal in coordination with Israeli security, but in September 2001, the policy was changed after a Palestinian fired at an Israeli security guard in the zone. "They [Palestinians] haven't been allowed into the terminal since then," said Rami Hadad, deputy head of Karni. "All contact is conducted only by phone."

A daily average of 500 to 600 trucks pass through the terminal, although on particularly tense days, the number drops to 150 or less. While the war in Iraq had a negative impact on traffic, by yesterday "things were back to normal," said Hadad.

The trucks carry food, medicine, toys and textile imports that Gazans are unable to produce as well as a variety of exports that they try selling in Israel. Some 60 percent of the merchandise moving between the two sides are imported to Gaza with the rest being exported to Israel.

Due to the intifada, Israel established a system whereby a truck arriving from Israel with goods for Gaza unloads the merchandise on one side of a wall, which is rolled back after which the goods are loaded on to a Gazan truck. The process adds hours to the transportation of goods between Israel and Gaza. According to Hadad, the gunman in yesterday's incident slipped into the Israeli side when the wall rolled back to load a Gazan truck.

Overall trade between Israel and Gaza, the vast majority of which takes place through Karni, is estimated at NIS 1.5 billion a year.

In an incident yesterday in Rafah, at the other end of the Gaza Strip, a commander from Islamic Jihad group, Abdel-Hamid Abu el-Eish, was killed by rockets fired from an Israeli army watchtower, witnesses said.