U.S. already active in British portion of Iraq?

So it would seem, if we’re down near Basra:

In what appeared to be a separate operation deep in the south near the Iranian border, a ferocious battle between American troops and Shiite militants left at least 20 people dead and wounded scores more, Iraqi and American officials said.

The clashes, in Amara and Majjar al-Kabir, a pair of mostly Shiite towns just north of Basra, started early Monday. They were sparked by raids on what American officials described as a secret network involved in transporting “lethal aid” from Iran to Iraq, particularly deadly roadside bombs known as explosively formed penetrators, or E.F.P.’s.

Lt. Col. Christopher Garver, an American military spokesman in Iraq, said American troops have intensified their focus on finding and dismantling places where those weapons are built, like the towns raided Monday, because the weapons were especially hard to stop at the border. “It’s hard to catch because they are shipped as components, not completed weapons,” he said.

According to officials aligned with the Shiite cleric Moktada al-Sadr in Basra, the fighting involved members of Mr. Sadr’s Mahdi Army militia. The battle appeared to be the largest clash with Mr. Sadr’s loosely affiliated gunmen since the start of the new American security plan in February.

In addition to the 20 dead, six suspects were wounded and one was detained, officials said. A hospital official said that at least 60 people were wounded.

So, is British control slipping? Is the heat picking up in the south? And, if soon-to-be British PM Gordon Brown does go through with a British drawdown, how do we fill the gap?

Gen. Petraeus ain’t talking about this one, at least not in public.

I would say it would necessitate a minimum of 20,000 additional troops.