Israeli troops battled Hamas fighters in major cities of overcrowded Gaza today as Israel spurned appeals to halt a war on the Islamists that so far has killed at least 580 Palestinians. Israeli tanks backed by helicopter gunships pushed into the city of Khan Yunis in the pre-dawn hours, to be met by return fire from militant groups.

President George W. Bush says any cease-fire in the Mideast must be fully respected. Bush called the Hamas attacks an "act of terror" and said no peace deal would be acceptable unless the flow of smuggled weapons to terrorist groups is monitored and stopped.

Afghanistan's southern rim, the Taliban's spiritual birthplace and the country's most violent region, has for the last two years been the domain of British, Canadian and Dutch soldiers. But that's about to change as the U.S. prepares to pour at least 20,000 extra troops into the south, augmenting 12,500 NATO soldiers there.

The top U.S. military officer said that the Pentagon could double the number of American forces in Afghanistan by next summer to 60,000 -- the largest estimate of potential reinforcements ever publicly suggested.

Pakistan told India it did not want war and would use force only if attacked. The United States has been trying to ease the burgeoning crisis while also pressing Pakistan to crack down on militants Washington says were likely responsible for the Mumbai attack.