WASHINGTON, March 18 (Reuters) - Shortly before leaving for a trip to Israel, President Barack Obama on Monday said now was the time for Iran to take "immediate and meaningful steps" to reduce tensions with the international community over its nuclear program.

As he has done in previous years, Obama used the occasion of Iran's new year celebration to urge Tehran to resolve differences with Washington and other Western nations over its nuclear ambitions.

"Iran's leaders say that their nuclear program is for medical research and electricity. To date, however, they have been unable to convince the international community that their nuclear activities are solely for peaceful purposes," Obama said in a statement.

"Now is the time for the Iranian government to take immediate and meaningful steps to reduce tensions and work toward an enduring, long-term settlement of the nuclear issue," he said.

Obama said the United States preferred a peaceful, diplomatic solution to the dispute. Later this week the president will visit Israel and Jordan, where the topic of Iran is expected to be high on his agenda. (Reporting by Jeff Mason and Matt Spetalnick; Editing by Eric Beech)