A U.S. military commander in Baghdad says, despite post-election violence, Iraq's security situation is improving, as the strength of Iraqi security forces grows, and the ability of insurgents to mount massive attacks diminishes.

Brigadier General Donald Alston says Iraqi security forces have made great strides in numbers and capabilities. Speaking with reporters Thursday, the lead communications officer for the multinational force in Iraq said conditions in many parts of the country remain perilous, but are markedly improved from a year ago.

"The calculus has changed, because we have 223,000 Iraqi security forces that are in the fight," General Alston said. "The calculus has changed because Iraqi security forces are now deployed throughout the country. The calculus has changed because the Iraqi security forces are doing a better job manning and securing their borders, which is denying and disrupting the flow of the critical sustenance that comes from outside the country to support Zarqawi's efforts."

General Alston said insurgents and terrorists, led by Jordanian-born Abu Musab al-Zarqawi, have shown themselves unable to sustain the massive, spectacular bombing attacks that were all too common last year, despite surges in post-balloting violence, most recently after Iraq's national elections earlier this month.

"Just as we expected and saw for the [constitutional] referendum [earlier this year], once elections security measures were lifted, attacks increased," continued General Alston. "We are seeing that now, as well. However, the insurgency is showing little capacity to sustain numerous and persistent elevated attack levels."

The general said insurgents have increasingly turned to smaller-scale attacks, and that even these less-lethal incidents should diminish over time. He gave credit to Iraqi security forces, but said political participation by Iraq's disgruntled Sunni minority has also been helpful, saying, "the choice of ballots over bullets was a very positive development."

Thursday, a suicide bomber killed four police officers in Baghdad, while gunmen killed at least 11 people in Latifiyah.

Critics of the war in Iraq have alleged that the pace of training Iraqi security forces has been too slow, and that disbanding the country's army after the 2003 U.S.-led invasion was a mistake.