LONDON — Financial markets and political leaders reacted with initial relief Monday to the results of the Greek elections, which eased fears that the country will leave the euro and unleash further turmoil on the beleaguered single currency.

But they warned that any rally could be short-lived, as few predict an early or easy resolution to the euro zone’s problems.
European markets opened immediately higher Monday, with Frankfurt and Paris up 1 percent to 2 percent, following a rally in Asian markets, where stocks rose around 2 percent and the euro rose against the dollar.
The election results, however, are destined to spark a period of intense horsetrading among political parties in Greece to form a coalition government, followed by a second negotiation to secure concessions on loan terms from international lenders.
While that process gets under way, leaders of the Group of 20 nations were due to meet later Monday in Los Cabos, Mexico, with the euro zone crisis likely to figure prominently in discussions.
The Greek vote, which left the pro-euro, center-right New Democracy party with the task of forming a new government, gives European leaders a brief respite, relieving some of the intense pressure on them ahead of a crucial summit in Brussels at the end of the month, when they are due to discuss fundamental changes to the structure of the single currency.
But the scale of support for the Greek radical leftist party Syriza, which won more than a quarter of the vote, underlined the extent of the opposition in Greece to the strict austerity terms being imposed on the country by international lenders, and suggests that the euro zone is likely to face weeks, or even months, of further political tension.
“Is euphoria appropriate in these circumstances? I wouldn’t say so,” said Kenneth Wattret, chief euro zone economist at BNP Paribas in London. “But there is relief because the election outcome could have been more problematic.”
Mr. Wattret said the respite should help bring down yields, or interest rates, on the sovereign bonds of troubled countries like Spain, a measure of borrowing costs that has been spiking to near-unsustainable levels on fear that the euro crisis would spread.
“But the question is how long that lasts,” he said. “We have been in this crisis for some time and markets have got used to something positive happening and then enthusiasm starts to wane.”
In Athens, with most of the votes tallied, New Democracy led with 29.6 percent of the vote and 129 of the 300 seats in Parliament. Syriza had 26.9 percent and 71 seats, and the center-left Pasok party was in third with 12.3 percent of the vote and 33 seats. The extremist far-right Golden Dawn party surprised some by maintaining its level of support from the last election on May 6, securing 6.9 percent of the vote and 18 seats.
With Syriza pledging to stay out of government and lead opposition to austerity, political leaders and financial markets know that the political situation in Athens remains complex. Pasok officials had said they would insist on Syriza being part of any coalition they would join, though it is unclear whether or not this is a negotiating ploy.
While Greece’s international lenders insist that the basis of the bailout agreement must stay intact, there is speculation that Athens might be given more time or better terms to pay back loans, and that European funds might be used to try to spark economic activity.
“You are betting on the ability of the Greek politicians to form an effective coalition government and making a judgment on the leeway there is to re-negotiate their program,” said Mr. Wattret of BNP Paribas. “It is pretty obvious that the current arrangements require adjustment, but there is a balance between what Greece wants and what the other member states will accept.”
In a joint statement issued late Sunday from Los Cabos, Herman Van Rompuy, president of the European Council, and José Manuel Barroso, president of the European Commission, said that they were “hopeful that the election results will allow a government to be formed quickly.”
“We will continue to stand by Greece as a member of the E.U. family and of the euro area,” they said.
The statement added that previous aid agreements between Greece and its euro zone partners formed “the basis upon which to build to foster growth, prosperity and jobs for the Greek people.”
Greece’s choice was also welcomed by the finance ministers of the euro zone countries, who said in a statement Sunday night that the outcome of the vote “should allow for the formation of a government that will carry the support of the electorate to bring Greece back on a path of sustainable growth.”
Steffen Kampeter, a deputy to Finance Minister Wolfgang Schäuble of Germany, underlined the expectation from Berlin that a new Greek government will uphold its commitments to Europe and the euro zone in an interview with ARD public television, calling the outcome a “chance for Greece to return to growth and stability.”
Greece’s financial troubles also remain a considerable worry for Chinese policymakers, whose stakes in the euro region include significant direct investment.
“The Greek election results unfortunately don’t seem to offer any clarity on the policy measures needed to keep Greece in the euro zone and stabilize its public finances,” said Fred Hu, an economist who has advised Chinese policymakers for years and is now the chairman of Primavera Capital, a Beijing-based private equity firm. “The last thing investors need is heightened political uncertainty and policy paralysis, which has gripped Greece.”
In Asian trading, the Nikkei 225 stock average in Tokyo rose 1.8 percent, while the Hang Seng index in Hong Kong rose 1.2 percent. Banking stocks led European indexes more than 1 percent higher.
U.S. equity index futures were trading higher, suggesting Wall Street stocks would be up later at the opening bell. The Standard & Poor’s 500 index gained about 1 percent on Friday.
The euro rose, but eased off of gains earlier in Asian trading. It climbed to $1.2685 from $1.2638 late Friday in New York.
The British pound fell to $1.5680 from $1.5715. The dollar rose to 79.26 yen from 78.73 yen, but fell to 0.9464 Swiss francs from 0.9501 francs.
The European sovereign bond market was calm. The yield on the Spanish 10-year government bond fell 5 basis points to 6.75 percent. The yield on comparable Italian debt fell 3 basis points to 5.87 percent.
Martin Schulz, president of the European Parliament, who was the only European official to have visited Greece between the two rounds of parliamentary elections, underlined the expectation from Brussels that any newly formed Greek government accept the basic principles of the so-called memorandum of understanding agreed to by both parties.
He recalled that in the past, the leader of New Democracy, Antonis Samaras, had not always been supportive of the efforts to help Greece restructure its economy and remain in the euro zone. “For quite a while, Mr. Samaras refused to accept the measures with the European Union,” Mr. Schulz, who is German, told ARD public television on Sunday. “But I trust him to become a responsible partner.”
He stressed that Europe remained willing to help Greece, as long as Greece is willing to accept what Europe expects of it, acknowledging that it would not be easy.
“The path ahead of the Greeks is difficult,” Mr. Schulz said. “But outside of the euro zone it certainly would have been even more difficult.”
Rachel Donadio in Athens, Keith Bradsher in Kong Kong, Melissa Eddy in Berlin and David Jolly in Paris contributed reporting.