UNITED NATIONS - UN Secretary-general Ban Ki-moon on Wednesday welcomed the ceasefire between Israel and Hamas, and commended Egyptian President Mohamed Morsi for leading the efforts to reach the ceasefire.

"I warmly welcome today's ceasefire announcement," said Ban while briefing the UN Security Council via video link from the Tel Aviv airport. "I commend the parties for stepping back from the brink and I commend President Morsi of Egypt for his exceptional leadership."

UN Secretary-General Ban Ki-moon (L) and Palestinian President Mahmoud Abbas hold a joint news conference in the West Bank city of Ramallah Nov 21, 2012.[Photo/Agencies]

The secretary-general was visiting the Middle East region to push for an early end to the week-long hostilities between Israel and Palestinian militant groups in Gaza.

Egyptian Foreign Minister Mohamed Kamel Amr announced the ceasefire accord in Cairo on Wednesday evening. The ceasefire officially came into effect at 9:00 pm local time (1900 GMT).

According to the Egyptian state news agency MENA, the ceasefire agreement stipulated Israel stop all hostile ground, sea and air operations on the Gaza Strip, including invasions and operations targeting individuals. Meanwhile, it also stipulated the Palestinian factions stop all hostile operations toward Israel, including launching rockets and attacking border area.

"Our focus now must be on ensuring the ceasefire holds and that all those in need in Gaza -- and there are many -- receive the humanitarian assistance they need," Ban said. "It's a huge relief for the people of Gaza and Israel, and for the international community, that the violence is stopping."

"But we are all aware of the risk, and we are all aware that there are many details that must be solidified for a broad, durable ceasefire to take firm hold over the longer term," he said. "It is imperative that both sides stick to the ceasefire in order to allow these underlying issues to be addressed in a sustainable fashion."

"Today's announcement follows a week of devastating violence in southern Israel and Gaza, including the terror attack today on a bus in downtown Tel Aviv, which I strongly and immediately condemned," said the UN chief. "This brought us to an important moment, after a week of intense diplomacy, to reach a ceasefire."

Ban was on a three-day visit to Egypt, Israel, the occupied Palestinian territory and Jordan, during which he met with regional leaders to push for an early truce.

"Since the situation in Gaza and Israel escalated last week, I made it my priority to contribute to efforts to halt the violence, with the priority aim of protecting civilians," Ban said.

"I canceled a previously-planned trip to travel to the Middle East instead, as a clear signal of the need for international diplomatic mobilization to prevent a further escalation that would put the whole region at risk, and to strengthen the commendable efforts led by Egypt to reach a ceasefire," he said.

"My paramount concern throughout has been for the safety and well-being of all civilians, no matter where they are," he said. " Innocent people, including children, have been killed and injured on both sides."

The Israel-Hamas conflict has reportedly left more than 140 Palestinians and at least five Israelis killed, and about 1,000 others injured on both sides.

"It is unacceptable for citizens on both sides to permanently live in fear of the next strike," said Ban. "Put simply, all parties must respect international humanitarian law to ensure the protection of all civilians, at all times."

"The humanitarian crisis is growing exponentially the longer the crisis continues," he said. "We need a ceasefire now, followed immediately by negotiations on the underlying issues. That is the sequence that can save lives now."

"The current crisis underscores that the status quo is unsustainable, and that long-term solutions must be found to the problems of Gaza, and for the Palestinians as a whole," he added.