WASHINGTON — The Obama administration, increasingly alarmed by the spillover effects of Europe’s financial crisis, has begun an intensive lobbying campaign to persuade Chancellor Angela Merkel of Germany and other leaders to ramp up efforts to stem any contagion from the debt crisis in Greece.

In phone calls and meetings over the last week, President Obama urged Mrs. Merkel and President Nicolas Sarkozy of France to take coordinated measures — including spending billions in additional funds to bail out Greece and bolster European financial institutions — to prevent Greece’s debt woes from spreading to its neighbors.

The American pressure was on display again Friday and will be this weekend at a gathering of the world’s finance ministers in Washington.

Yet administration officials played down the likelihood of concerted action emerging from these meetings of the International Monetary Fund and the World Bank. At best, they said, the ministers might lay the groundwork for a bolder response in November, when leaders of the Group of 20 industrialized nations meet in Cannes, France.