Iran's launch of its first satellite into space is a grave cause for concern to the U.S. as the Islamic Republic continues to work toward developing long-range missile capability, the Pentagon and White House said Tuesday.

Tuesday's launch of its first domestically made satellite "does not convince us that Iran is acting responsibly to advance stability or security in the region," said White House Press Secretary Robert Gibbs. 

Gibbs said any effort to develop missile delivery capability, continue an illicit nuclear program, threaten Israel and sponsor terror is an "acute concern to this administration."

"It is certainly a reason for us to be concerned about Iran and its continued attempts to develop a ballistic missile program of increasingly long range," Pentagon press secretary Geoff Morrell told reporters Tuesday. 

"They (Iran) pose a real threat and it is a growing threat," he said.

Iran sent its first domestically made satellite into orbit, Iranian President Mahmoud Ahmadinejad announced Tuesday -- claiming a significant step in an ambitious space program that has worried many international observers.

The satellite -- called Omid or "Hope" in Farsi -- was launched late Monday on the 30th anniversary of the 1979 Islamic revolution.

The launch came one day before Secretary of State Hillary Clinton met with foreign ministers to discuss Iran's nuclear ambitions. She announced that senior U.S. diplomat William Burns will join officials from other major powers in Germany Wednesday to map out a strategy for thwarting Iran's nuclear ambitions.

Clinton said Tuesday that the U.S. must adopt policies that show an openness to dialogue and diplomacy, but said it is imperative that Iran act similarly.

"We are reaching out a hand, but the fist has to unclench," Clinton said at a news briefing with Britain's Foreign Secretary David Miliband, repeating a line from Obama's inauguration speech.

Miliband called the Obama administration's willingness to talk to Iran a "new dimension" in international efforts to end Tehran's nuclear ambitions.

"Anything which adds to the international tension should be of concern," he said.

German Foreign Minister Frank-Walter Steinmeier also expressed concern over the launch, saying that the reports -- if confirmed -- are an alarming development and an unsettling sign of Iran's progress in transport technology.

"That's why we must, with the new U.S. administration, intensify our efforts in the six-state group to dissuade Iran from the development of a militarily serviceable nuclear program," Steinmeier said. 

Earlier Tuesday, state Department spokesman Robert Wood also called the development notable and cause for "grave" concern.

"Developing a space launch vehicle that could be -- could put a satellite into orbit could possibly lead to development of a ballistic missile system," he said during a State Department briefing Tuesday. 

FOX News' Jennifer Griffin contributed to this report.