The bodies of two Palestinians shot dead overnight in northern Gaza by Israeli troops were recovered Thursday by Palestinian medical officials.

Adham Abu Selmiya, the spokesman for the Hamas-run health services in the Gaza Strip, said an ambulance found the bodies of the two men on Thursday morning.

Hamas and Islamic Jihad members have received training in Lebanon, Syria and Iran and returned to the Gaza strip to train other fighters, Israeli daily Haaretz reported.

The newspaper said that Iranian and Syrian experts have also improved the fighting capabilities of Hamas and Islamic Jihad militants as part of an operation to restructure the force of Palestinian factions that was destroyed during Israel's last aggression on Gaza.

Two suspected Palestinian militants died and an Israeli soldier was wounded late Saturday in an exchange of gunfire near the border of the Gaza Strip with Israel, the Israeli army announced.

Soldiers spotted the two Palestinians near the security barrier separating Israel from Hamas-controlled Gaza and opened fire, killing them after a gun battle lasting some 20 minutes, an army spokesman said.

Israel carried out two air raids on the Gaza Strip early Wednesday without causing any casualties, Palestinian security officials said.

The attacks came after Palestinian militants fired two projectiles into southern Israel from the Hamas-ruled Gaza Strip on Tuesday.

Five Palestinians were injured Tuesday by Israeli gunfire while scrounging for construction material in the rubble near Gaza's northern border with Israel, Palestinian medics said.

The Israeli military said it had opened fire on three Palestinians approaching the border fence after they failed to respond to warning shots.

The United States on Wednesday urged "all those wishing to deliver goods to do so through established channels so that their cargo can be inspected and transferred via land crossings into Gaza."

"As we continue to make clear to involved parties, mechanisms exist for the transfer of humanitarian assistance to Gaza," the U.S. State Department said in a statement.

The EU's refusal to accept Turkey as a member swiftly has partly caused Ankara's foreign policy shift and the deterioration in its relations with Israel, U.S. Defense Secretary Robert Gates said Wednesday.

"The deterioration in the relationship between Turkey and Israel over the past year or so is a matter of concern," Gates told reporters in London.

Israel's deadly raid on an aid flotilla for Gaza was a tragedy that demands detailed investigation and must not be repeated, Russian Prime Minister Vladimir Putin told Agence France Presse in an interview.

"What is especially tragic is that this act was carried out in neutral waters," the Russian prime minister said in a discussion late Monday in the Black Sea resort town of Sochi.

Israel on Wednesday was discussing the format of an investigation into its deadly raid on a Gaza-bound flotilla, but Prime Minister Benjamin Netanyahu insisted soldiers would be off-limits.

Israel was in talks with "several members of the international community" about the investigation, Netanyahu said, stressing that it should focus on "the pro-Palestinian activists who fought the naval commandos with knives and clubs."

President Barack Obama Wednesday pledged unwavering commitment to forge significant progress in the Middle East this year, despite the furor whipped up by Israel's raid on a Gaza aid flotilla.

Welcoming Palestinian President Mahmoud Abbas to the White House, Obama promised the "full weight" of U.S. diplomacy on the latest crisis and to push Israelis and Palestinians out of a "dead end" and into direct peace talks.