Israel test-fired a missile on Wednesday, two days after Prime Minister Benjamin Netanyahu warned of the direct and heavy threat posed to the Jewish state by Iran's nuclear programme.

Israel today carried out the test-firing of a rocket propulsion system from the Palmachim base, a Defence Ministry statement said. This had been long planned by the defence establishment and was carried out as scheduled.

The missile flew at a high angle skyward, its plume visible across central Israel, according to witnesses who informed local media of the launch before the ministry formally announced it.

The ministry declined to elaborate on the system tested, but Israel Radio's military affairs correspondent, who is regularly briefed by top officials on defence matters, said a ballistic missile had been launched.

The term generally applies to long-range missiles for delivering warheads. Israel, which neither confirms nor denies having such weapons, known as Jerichos, has also been upgrading its Arrow aerial shield, which uses interceptor missiles to shoot down incoming ballistic missiles above the atmosphere.

Israeli media have carried a flurry of reports on purported efforts by Prime Minister Netanyahu to secure cabinet approval for military action against Iran. Some analysts say the speculation is designed to jolt world powers into toughening sanctions on Tehran.

Asked about the media speculation, a spokesman for Netanyahu declined to comment, saying the prime minister had spoken about Tehran's nuclear programme in a policy speech on Monday that opened parliament's winter session.

A nuclear Iran will pose a serious threat to the Middle East and the entire world, and it of course poses a direct and heavy threat to us, Netanyahu said in that address, echoing comments he has made in the past.

Netanyahu gave no hint on what action Israel might take. He has said that all options are on the table in trying to stop Iran from building nuclear arms. Iran says it is enriching uranium for peaceful purposes.

PRECEDENTS

The Israelis bombed Iraq's nuclear reactor in 1981 and launched a similar sortie against Syria in 2007, precedents lending weight to their veiled threats to take similar action on Iran if foreign pressure fails to curb its uranium enrichment.

But many independent analysts see the mission as too much for Israel to take on alone against Iran.

Though reputed to have the Middle East's sole atomic arsenal along with a technologically superior air force, Israel lacks long-range bombers which could deliver lasting damage to Iran's distant, dispersed and fortified facilities.

And Washington has spoken out against such unilateralism by Israel, already isolated in a region of spiralling instability. Iran, which denies seeking nuclear arms, has vowed to retaliate against Israel and U.S. interests should it come under attack.

Raviv Drucker, political commentator for Israel's Channel 10 television, saw both diplomatic and domestic gains for Netanyahu in the media focus on a military option, which followed a lopsided October 18 prisoner swap with the Palestinian Islamist movement Hamas.

Israel also hopes to help stiffen world pressure on the Iranians around an upcoming publication by the U.N. nuclear watchdog that Western diplomats say will include intelligence about military aspects to their nuclear project.

This speculation works rather well for Netanyahu, as he can be portrayed as keen to deal with Iran, but is being 'held back' by others, Drucker said, referring to reports of opposition within the Israeli cabinet and security services to a military strike.

Israel's its strikes on Iraq and Syria were surprises. Israeli officials still refuse to discuss the latter raid, against a desert site the United States described as a North Korean-supplied reactor, amid denials from Damascus.

Iran has called for Israel's elimination, prompting Netanyahu to liken it to the Nazis -- potent rhetoric for a Jewish state born of the Holocaust.

The military option (against Iran) is not an empty threat, but Israel should not leap to lead it. The whole thing should be lead by the United States, and as a last resort, Moshe Yaalon, Israel's strategic affairs minister, told Army Radio on Tuesday.

(Writing by Dan Williams and Jeffrey Heller)