The world community has been intensifying relief efforts in Haiti in the past two days after a devastating quake hit the Caribbean nation on Tuesday.

On Saturday, a Boeing-747 jumbo jet carrying 90 tons of emergency humanitarian supplies provided by China took off from the Beijing Capital International Airport to quake-ravaged Haiti.

The 13 million yuan (US$1.9 million) worth of quake relief items included tents, stretchers, food, medicines, clothing and water purification equipment.

The aid is part of a relief package worth 30 million yuan (US$4.41million) the Chinese government announced Friday.

On Saturday, UN Secretary-General Ban Ki-moon said he was "deeply saddened to confirm the tragic death" of his special representative to Haiti Hedi Annabi, and Annabi's deputy Luiz Carlos da Costa.

"In every sense of the word, they gave their lives for peace," Ban said in a statement.

Annabi "was a true citizen of the world. The United Nations was his life and he ranked amongst its most dedicated and committed sons," Ban said. "He was passionate about its mission and its people."

Annabi, a Tunisian national who was head of the UN Stability Mission in Haiti (MINUSTAH), was found dead in debris in the quake-destroyed UN headquarters in Port-au-Prince by Chinese rescuers.

US President Barack Obama invited two of his predecessors, George W. Bush and Bill Clinton, to help raise relief funds for Haiti.

"I am pleased that President George W. Bush and President (Bill) Clinton have agreed to lead a major fund-raising effort for relief," Obama said in a joint appearance with his two predecessors after a meeting in the White House.

US Secretary of State Hillary Clinton arrived in Haiti to beef up US assistance to the country.

"I am confident that this Caribbean nation can come back better and stronger after the joint reconstruction work," Clinton told media at the airport, after meeting Haitian President Rene Preval.