Further clashes test already fragile ceasefire between Israel and Gaza militants

Palestinian militants in the Gaza strip sent a series of fire-carrying balloons across the border with Israel for a second straight day, further testing the fragile ceasefire that ended last month's war between Israel and Hamas.

The latest round of violence began Tuesday,prompted by a parade of Israeli ultranationalists through occupied East Jerusalem. Palestinian militants saw the march as a provocation and sent balloons into southern Israel, causing several fires in parched farmland. Israel then carried outairstrikes the first such raids since the May 21 ceasefire ended 11 days of fighting and more balloons followed.

The airstrikes targeted facilities used by Hamas militants for meetings to plan attacks, the Israeli army said. There were no reports of injuries.

"The Hamas terror organization is responsible for all events transpiring in the Gaza Strip, and will bear the consequences for its actions," thearmy said. It added that it was prepared for any scenario, "including a resumption of hostilities."

By Wednesday afternoon, masked Palestinians sent a number of balloons into Israel, laden with fuses and flaming rags. Several fires were reported.

The unrest provided the first test of the ceasefire at a time when Egyptian mediators have been working to reach a longer-term agreement. It comes as tensions have risen again in Jerusalem, as they did before the recent war, leading Gaza's Hamas rulers to fire a barrage of rockets at the holy city on May 10. The fighting killed more than 250 Palestinians and 13 people in Israel.

An Egyptian security official said his government has been in "direct and around-the-clock" contacts with Israeli officials and the Gaza rulers to keep the ceasefire and to urge them to refrain from provocative acts.

The official, speaking on condition of anonymity because he was discussing behind-the-scenes diplomacy, said the U.S. administration has also been in touch with Israel as part of the efforts.

The two sides seem to agree "not to escalate to the tipping point," he said. "And we do every effort to prevent this."

The flare-up also has created a test for Israel's new government, which took office early this week. The diverse coalition includes several hard-line parties as well as dovish and centrist parties, along with the first Arab factionto be part of an Israeli government.

Keeping the delicate coalition intact will be a difficult task for the new prime minister, Naftali Bennett.

In Tuesday's parade, hundreds of Israeli ultranationalists, some chanting "Death to Arabs," marched in East Jerusalem in a show of force. Hamas called on Palestinians to "resist" the parade, which was meant to celebrate Israel's capture of East Jerusalem in 1967. Palestinians consider it a provocation.

In a scathing condemnation on Twitter, Foreign Minister Yair Lapid, who heads the centrist Yesh Atid Party, said those shouting racist slogans were "a disgrace to the Israeli people."

Bennett, who will hand over the prime minister's job to Lapid after two years, is a hard-line Israeli nationalist who has promised a pragmatic approach as he presides over a delicate, diverse coalition government.

Though there were concerns the march would raise tensions, cancelling it would have opened Bennett and other right-wing members of the coalition to intense criticism from those who would view it as a capitulation to Hamas.

Mansour Abbas, whose Raam party is the first Arab faction to join an Israeli coalition, said the march was "an attempt to set the region on fire for political aims," with the intention of undermining the new government.

Abbas said the police and public security minister should have cancelled the event.

While the parade provided the immediate impetus for the balloons, Hamas is also angry because Israel has tightened its blockade of the territory since the ceasefire. The restrictions include a ban on imports of fuel for Gaza's power plant and raw materials.

Israel imposed the blockade after Hamas, a militant group that seeks Israel's destruction, seized control of Gaza from the internationally recognized Palestinian Authority in 2007. Israel and Hamas have fought four wars and numerous skirmishes since then. Israel says the blockade, enforced with Egypt, is needed to prevent Hamas from importing and developing weapons.

After capturing East Jerusalem in 1967, Israel annexed the area in a move not recognized by most of the international community. It considers the entire city its capital, while the Palestinians want East Jerusalem to be the capital of their future state. The competing claims over the area, home to Jewish, Christian and Muslim holy sites, lie at the heart of the conflict and have sparked many rounds of violence.