A leader of Hamas (search) on Sunday accused Israel of violating a recent cease-fire agreement, hinted the militant group is using the current period of calm to rearm itself and warned that tensions over Jerusalem could quickly spill over into violence.

Hamas, which is expected to win a large share of seats in Palestinian parliamentary elections in July, also will oppose any peace agreement with Israel, said Mahmoud Zahar (search), one of the group's top figures in Gaza.

In a statement published in the Al Quds daily, Zahar criticized Israel's announcement last week that it plans to expand Maaleh Adumim, a major settlement near Jerusalem.

The planned construction would link the settlement to Jerusalem, separating Arab neighborhoods of the city from the rest of the West Bank (search). The Palestinians claim all the West Bank as part of a future independent state, with east Jerusalem as their capital.

"What Israel is doing in Jerusalem is a great violation for the calm that was declared by the Palestinian factions," he said.

Hamas, Islamic Jihad and other militant groups agreed this month to halt attacks on Israel for the rest of the year, provided Israel halts its military activity against them. Israel has promised to respect the truce as long as the situation remains quiet.

Zahar did not threaten any immediate violence, but said his group would strike hard if Jewish extremists follow through on a pledge to storm a disputed holy site in Jerusalem.

Extremists have said they would like to force their way into the site, known to Jews as the Temple Mount and Muslims as the Noble Sanctuary (search), in an attempt to sabotage Israel's planned withdrawal this summer from Gaza and part of the West Bank.

"If the Al Aqsa mosque is attacked by Jewish fanatic groups, Hamas' response will be tough and shake Israel, which knows very well that we have the capabilities," he said.

Israel's military chief, Lt. Gen. Moshe Yaalon, has accused militants of using the cease-fire to rebuild their arsenals after more than four years of fighting with Israel.

Zahar responded by saying there have been "hundreds" of Israeli violations of the cease-fire. "Since we do not agree with the Israeli (Yaalon's) statement there, it is logical that the movement must be aware of any Israeli violation," he said.

Hamas is expected to make a strong showing in the July 17 Palestinian election. Although the group has shown no signs that it wants to bring down Palestinian leader Mahmoud Abbas, control of parliament could hamper Abbas' ability to negotiate a peace deal with Israel.

Zahar said the group would use its parliamentary leverage to resist any peace agreement with Israel. Hamas believes all of the region, including Israel, is Islamic land.

"Hamas is not going to accept during its mandate in the upcoming Palestinian legislative council to sign any peace agreement with Israel that gives Israel the right to take over any inch of the Palestinian land," he said.

Zahar also criticized reported land deals under which the Greek Orthodox Church turned over sensitive property in Jerusalem to Jewish settler groups. The alleged deals have prompted calls by Palestinian Christians for the Greek Orthodox patriarch, Irineos I, to resign.

"This is a very dangerous subject, an old-fashioned war by Jews against us using traitors and brokers and we are not going to accept that, and we are not going to keep silent," Zahar said. "What took place in Jerusalem is greater than all the Israeli crimes against our people."