Israeli radio said two of the suspects, both brothers, lived on the Adora settlement where four Jews were killed during a Palestinian attack on 27 April.
Soldiers accused
60,000 5.56mm bullets (for Galil and M-16 assault rifles)
3,000 9mm bullets (for Uzi submachine guns or 9mm handguns)
Source: Yediot newspaper
Earlier, Israel announced it would freeze moves to ease restrictions, which include curfews in seven Palestinians towns and cities in the West Bank.
The decision was taken in response to a double suicide bomb attack on Tel Aviv on Wednesday night in which two bombers and three other people were killed.
In the US, Secretary of State Colin Powell met Arab foreign ministers, Ahmed Maher of Egypt, Marwan al-Muasher of Jordan and Prince Saud al-Faisal of Saudi Arabia.
'Productive talks'
The Arab ministers would like to see the declaration of a Palestinian state, perhaps as early as January.
The US says it wants reforms first - including the election of a new Palestinian leader.
But Mr Powell sought to quash any talk of rifts and described the talks as "very productive".
Prince Saud al-Faisal said: "We are here on a journey. We are more encouraged by what we heard from the secretary today that this journey is going in the right direction."
President Bush is set to meet the foreign ministers at the White House later on Thursday.
'Tip of the iceberg'
The arrests of the soldiers followed tips of a vast smuggling operation of ammunition from Israel into the West Bank.
Ammunition theft from Israeli army bases has more than doubled in the last year.
In addition to ammunition smuggling, two of the soldiers - from the Telem settlement - are suspected of getting Palestinian lorries through checkpoints into Israel by taking the wheel in their military uniforms, newspapers reported.
"Only the tip of the iceberg has been uncovered in this case," the Yediot Aharonot newspaper said, quoting sources close to the investigation.
Peace 'drowned out'
At a seminar on the Middle East in Copenhagen, the United Nations co-ordinator for the Middle East peace process said the involvement of the international community was vital for peace in the Middle East.
Terje Roed Larsen - who helped bring the two sides together for the 1993 Oslo peace accords - said events in the region continued to be driven by those who were doing their best to prevent a solution.
Any spirit of peace that may have existed was being drowned out, he said, by violence, recriminations and distrust.
"The despicable terrorist attacks against Israeli civilians over the past two days just show how bad the situation has become," he said, referring to the Tel Aviv attack.
Attacks continue
Israeli Prime Minister Ariel Sharon now faces a difficult decision about how to proceed in his dealings with the Palestinians.
Since the end of March he has:
But despite all that Mr Sharon has tried, the attacks continue.
Our correspondent, James Reynolds, says that the problem for many Israelis is that no-one else has been able to come up with much of alternative.
Almost everything that has been seriously suggested, short of unilateral withdrawal from the West Bank and Gaza, has been tried.
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