Israeli Prime Minister Ehud Olmert speaks at a press conference held jointly with European leaders (not pictured) in Jerusalem, Jan. 18, 2009. Olmert said on Sunday that Israel will withdraw troops out of the Gaza Strip once a stable truce is guaranteed.

Israeli soldiers wait to go back by bus at Israel-Gaza border after returning from the Gaza Strip Jan. 18, 2009. The Israeli army has begun withdrawing its troops from the Gaza Strip on Sunday evening, local news service Ynet reported.

JERUSALEM, Jan. 18 (Xinhua) -- Israel will pull troops out of the Gaza Strip once a stable truce is guaranteed, said Prime Minister Ehud Olmert on Sunday, after his country and Hamas each declared a ceasefire.

"We intend to leave Gaza as soon as possible once we make sure that Israel's south is safe. We did not set out to take Gaza, and we have no desire to stay in it," he told visiting European leaders in the evening at his official residence.

The remarks came shortly after the Israel Defense Forces (IDF) began withdrawing part of its troops from Gaza in what it said was an overall redeployment. The army refused to reveal how many troops it will pull out at the current stage and when it will finish a complete withdrawal.

Recent local media reports indicated that thousands of regular troops and an additional several thousand reservists had entered Gaza since Israel launched the ground incursion on Jan. 3.

The partial withdraw followed announcements in the afternoon from Hamas and other Gazan militant groups that they decided to stage a one-week ceasefire with Israel, during which Israel must withdraw its troops.

However, while noting a possible danger that "Hamas is going to deliberately torpedo the ceasefire" and the accompanying need for Israel "to re-initiate offensive actions," Olmert's spokesman Mark Regev said earlier in the day that "we can't talk about a timetable for withdrawal until we know the ceasefire is holding."

When declaring Israel's unilateral truce on Saturday night, Olmert said that the Gaza offensive, dubbed Operation Cast Lead, achieved all its goals, but Israel will keep its military presence in Gaza, and will consider the withdrawal only when Hamas entirely ends its rocket fire at Israel.

In a letter to the troops on Sunday, the IDF Chief of General Staff Gabi Ashkenazi stressed that the operation "has yet to be concluded, and the next several days call for us to remain alert and ready, until peace and quiet are restored to our cities."

Amid concerns over possible Palestinian attacks, Israel is widely expected to retain some forces in Gaza. The returning troops, said local news service Ynet, were stationed along the border.

In a sign of the fragility of the truce, Gazan militants fired at least 15 rockets at southern Israel on Sunday, injuring two people, and Israeli warplanes staged airstrikes at the launching sites in response.

Exchange of fire between Israeli soldiers and Gazan militants also occurred in northern Gaza, and a Palestinian farmer was shot dead in southern Gaza by Israeli troops who claimed that he was approaching the military zone.

Clashes subsided at night. Should a respite be in place, it would bring a pause to the three weeks of bloodshed across the Israel-Gaza border, during which over 1,300 Gazans have been killed and 13 Israelis have also died.

A temporary lull would also pave the way for a possible lasting truce deal between the Jewish state and the Islamist movement, in light of the intensifying international mediation efforts led by Egypt.

While Hamas sets conditions for any long-term truce by asking for the lifting of blockade Israel imposed on Gaza, Israel demands an international mechanism to curb arms smuggling into Gaza and thus prevent Hamas from rearming.

Speaking to the leaders of Britain, France, Germany, Italy and the Czech Republic, which currently holds the rotating EU presidency, Olmert thanked them for their support for Israel's security and pledged cooperation to bring peace to the volatile land.

The guests, who earlier attended a summit in Egypt with Arab leaders and UN Secretary-General Ban Ki-moon on the Gaza situation, called for a lasting peace between Israel and the Palestinians, which requires an end to hostilities and the removal of the Gaza siege among others.