JERUSALEM (Reuters) - Right-wing leader Benjamin Netanyahu on Friday accepted a mandate to form Israel's next government and immediately called for a broad, national unity coalition with centrist and left-wing partners.
Such a coalition might create a stable, middle-of-the-road government immune to the sort of pressure from fringe parties that has hamstrung previous Israeli administrations.
But there was no sign that his rivals would accept, and Netanyahu may have no alternative but an alliance with far-right and ultra-religious parties, which could tie his hands on making peace with the Palestinians and tightening fiscal discipline.
Palestinians and Arab neighbors were likely to see his nomination as confirmation that most Israelis are in no hurry to pursue peace deals with them.
Netanyahu, 59, leads the hawkish Likud party. He was prime minister before in the late 1990s and now has six weeks to put together a coalition for a second turn at the helm.
Likud more than doubled its seats in the election 10 days ago in which the security of the Jewish state was the paramount issue, after a 2006 conflict with Hezbollah Islamists in Lebanon and a war with Islamist Palestinian Hamas in Gaza last month.
But there was no clear winner.
With 27 seats in the 120-seat Knesset, Netanyahu ended up one seat behind the centrist Kadima party of Tzipi Livni, the dominant partner in the outgoing coalition.
The electorate's rightward drift, however, gave him a better chance of achieving a majority with like-minded parties.
But his nomination by President Shimon Peres on Friday was a break with Israeli tradition, which has always given a governing mandate to the leader of the first-placed party after elections.
Netanyahu urged his opponents to close ranks.
"I call on Kadima chairwoman Tzipi Livni and Labor Party chairman Ehud Barak and I say to them -- let's unite to secure the future of the State of Israel."
Repeating his campaign message, he said Iran was seeking nuclear weapons that could threaten Israel and was challenging Israel through Islamist proxies, Hezbollah in south Lebanon and Hamas in Gaza.
In the Gaza Strip, a spokesman for the ruling Palestinian Hamas movement predicted conflict and instability.
"This means that Zionist policy is going from bad to worse," he said. "The nomination of Netanyahu does not point to security, peace or stability in the days ahead."
Livni, 50, said on Friday she was not interested in joining Netanyahu in any coalition "that doesn't allow me to pursue my path, the path of Kadima as we promised the voters."
Yoel Hasson, who leads Kadima's parliamentary group, told Reuters the party's lawmakers would meet on Sunday.
"I imagine the decision will be that we are going into opposition," he said. "We won't enter any government headed by Netanyahu."
But some in Kadima urged Livni to negotiate a coalition with Netanyahu, and the two may meet on Sunday after Netanyahu telephone to invite her for talks, party officials said.
"We didn't go to the elections in order to sit in opposition," Parliament Speaker Dalia Itzik of Kadima said told Channel 2 television. "I hope very much we can set up a government where Kadima has a central role."
Netanyahu's rivals to the left favor pursuing talks with secular Palestinian leaders, backed by U.S. President Barack Obama, that could hand most of the occupied West Bank and parts of Jerusalem to a new Palestinian state in return for peace.
U.S.-educated Netanyahu, who had poor ties with the Clinton administration as premier, says Israel's unilateral ceding of occupied Arab land, notably Gaza in 2005, has backfired.
"I don't see much (peace) progress happening regardless of which coalition he forms," said analyst Eliezer Don-Yehiya.
Accepting his mandate, Netanyahu also noted that "the most serious world economic crisis in 80 years threatens the jobs of hundreds of thousands of Israelis."
The former finance minister championed welfare cuts and free-market practices in the early part of this decade, but to close a coalition deal with smaller parties he may have to agree to budget for more social benefits.
(Additional reporting by Allyn Fisher-Ilan)
Editing by Alastair Macdonald