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 program. "Israel today carried out the test-firing of a rocket propulsion system from the Palmachim base," a Defense Ministry statement said. "This had been long planned by the Defense 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 Defense 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.