The Israel-Iran conflict has escalated into its fourth day with mounting casualties, widening attacks, and no sign of diplomatic resolution.

Israel says Iran is targeting civilians as the Israeli military hammers Iranian launch sites and says it controls Tehran's skies.

But Israel's formidable and sophisticated military forces - with an arsenal largely, but not exclusively, provided by the United States - are enabling it to overpower a much larger enemy. The BBC looks at the military balance in the latest war in the Middle East.

The warning came on the fourth day of the conflict, when the Israeli military claimed it had achieved air superiority over the Iranian capital and could fly over the city without facing major threats.

Stocks are down on Friday, with oil prices surging in the wake of the Israel's military strike on Iran. The S&P 500 slid 48 points, or 0.5%, to 5,998 points in early trading, while the Dow Jones Industrial Average dropped 559 points,

Out of precaution, the U.S. withdrew diplomats from Iraq on Wednesday and authorized the voluntary departure of U.S. military families from the Middle East should such an attack occur and prompt retaliation by Iran, the Times and CBS News reported.