Prime Minister Ehud Olmert on Tuesday said the return of two soldiers being held by Hezbollah guerrillas in Lebanon is far off, dashing hopes that a prisoner swap a day earlier would pave the way for a bigger exchange.

Monday's exchange of three bodies and one prisoner on the heavily guarded Israeli-Lebanese border was the fourth between Hezbollah and Israel in recent years.

Although the swap was small in scale, its success was widely seen as improving the chances of further exchanges. Hezbollah even had some rare positive words for Israel, praising the exchange "as an expression of humanitarian goodwill by both sides."

In a speech broadcast on national radio Tuesday, Olmert urged caution, saying it would be a long time before Israel brought home the two soldiers, Ehud "Udi" Goldwasser and Eldad Regev, whose capture by Hezbollah sparked a 34-day war last year.

He also said it would take time to bring home a third captured soldier, Cpl. Gilad Shalit, who is being held in the Gaza Strip by Hamas-linked militants.

"Yesterday we passed a certain stage of the process but unfortunately, as I said, the process of returning Udi and Eldad in the north and Gilad in the south is long," Olmert said in a speech in the southern town of Ashdod.

In Monday's deal, Israel sent one prisoner and the bodies of two Hezbollah guerrillas to Lebanon in return for the corpse of a drowned Israeli civilian. The International Red Cross served as an intermediary,

Hezbollah also said it had transmitted to a U.N. mediator some "information relating to humanitarian issues that are of common interest" to Israel and the militant group.

"Hezbollah hopes that this goodwill gesture will help bring about progress to end all issues pertaining to the prisoners and the detainees," the group said.

Both Lebanese observers and Israeli media speculated the statement could refer either to the two abducted soldiers, or to Ron Arad, an Israeli air force navigator who disappeared after his plane was shot down over Lebanon in 1986.

The Lebanese newspaper al-Akhbar said Hezbollah had turned over papers dating back to Arad's capture and written in his handwriting.

Israel's government said the exchange was linked to efforts to win freedom of the two Israeli soldiers captured last year.

Their abductions, in a cross-border raid, prompted Israel to launch a war against Hezbollah. As many as 1,200 Lebanese, mostly civilians, and 160 Israelis, including 40 civilians, were killed in fighting.

Hezbollah has given no signs of life of the two men, who were severely wounded during the abduction, and it has not allowed the Red Cross to see them.

In his speech, Olmert said the government has never stopped trying to bring its soldiers home and said "processes are taking place behind the scenes."

"For years, our enemies have tried to raise the price that Israel pays for fragments of information and more than that, the return of kidnapped soldiers and civilians, or God forbid, bodies," he said.

"We're talking about an ugly and cynical bargaining over the Israeli public's emotions and sensitivities," he added. "Sometimes we have no choice but to pay the painful prices, but I was told that the deal completed last night was carried out fairly and for a price the state of Israel can pay."

The U.N. Security Council cease-fire resolution that halted the fighting last year demanded that Hezbollah turn over the seized soldiers.

But Hezbollah has repeatedly said the two soldiers would be freed only in exchange for freedom of all Lebanese prisoners held by Israel.

Israel is holding at least six Lebanese prisoners, including Samir Kantar, who has been imprisoned since 1979 for killing three members of an Israeli family.

His release would be extremely politically charged given the brutality of the killings. Kantar shot a man in front of his 4-year-old daughter, then killed the girl with his rifle butt. The man's wife smothered their 2-year-old daughter while hiding from Kantar in a crawl space in the family apartment.

Israel said the two Lebanese militants it handed over Monday were killed in the war last summer, and that the Hezbollah captive was released for medical reasons. The Israeli citizen handed over was a Jewish immigrant from Ethiopia who drowned in 2005, and whose body washed up on the Lebanese coast.