GAZA, Oct 14 (Nidal al-Mughrabi/Reuters) - Israel killed three Palestinians in the Gaza Strip on Sunday, a day after two men identified as the most senior al Qaeda affiliates in the enclave died in an Israeli air strike as they rode a motorcycle.

In southern Gaza, a Palestinian gunman was killed and another wounded near the border with Egypt's Sinai desert, hospital officials said. The Israeli military said the two, also targeted while on a motorcycle, had been planning to fire rockets into Israel.

A second air strike in central Gaza killed two more Palestinian militants and wounded two others. An Israeli military spokeswoman said the attack targeted a rocket launching squad.

Sources in the ultra-conservative Salafi Islamist movement said the two militants killed on Saturday, Hisham al-Saedni and Ashraf al-Sabah, were leaders, respectively, of the Tawhid wa-Jihad and Ansar Al-Sunna groups.

The movements share al Qaeda's vision of global jihad and oppose the more pragmatic Islamism espoused by Hamas and Cairo's politically dominant Muslim Brotherhood.

The men had recently merged their groups to form the umbrella Majles Shoura Al-Mujahideen (Holy Warriors' Guidance Council), the sources said, becoming the de facto heads of the diffuse Gaza jihadi network.

Their blood will be a light to guide the holy warriors through the right path and will be fire that will burn the Jews, one of the sources told Reuters, saying reprisals would not be limited to the short-range rocket launches that are Gaza militants' favored mode of attack on Israel.

The Salafi sources said Gaza-born Saedni, 47, had lived in Egypt and Jordan and had fought for al Qaeda in Iraq. He had been wanted by Egypt on suspicion of involvement in attacks on tourist sites there.

Israel said the militant, who was arrested by Hamas in 2011 and freed last August, had been behind a string of rocket and bomb attacks against the country and had planned to carry out a militant operation on its Sinai border.

The Global Jihad is stepping up its efforts to target us, and we will continue to interdict it with aggression and might, in terms of both response and pre-emption, Prime Minister Benjamin Netanyahu told the Israeli cabinet in Jerusalem on Sunday.

In a sign of Salafi assertiveness in Gaza, about 500 mourners attended Saedni's and Sabah's funerals on Sunday. Some wore the smocks typical of the al Qaeda bastions in Pakistan and Afghanistan but relatively uncommon among Palestinians.

Jihadi gunmen have raided Israel through the Sinai, a desert peninsula which has seen a surge of lawlessness during the political upheaval that has rocked Cairo since early 2011 including an Aug. 5 massacre of Egyptian border policemen that drew an unprecedented Egyptian security sweep.

Armed Salafis, while a fringe presence in Gaza, have been stepping up violence against Israel while at times clashing with the Palestinian Hamas government. They also operate in the Sinai. (Reporting by Nidal al-Mughrabi; Writing by Dan Williams; Editing by Rosalind Russell)