Pakistan says it intends to deploy a major unit of its regular army into the lawless tribal region that al-Qaida and Afghan insurgents use as a safe haven.

This would be an important step if it happens. The United States has pressed Pakistan to go after the Taliban and al-Qaida terrorists operating freely in the tribal areas on the western border with Afghanistan.

An army unit would supplement Pakistan's Frontier Corps, which is not very well trained and often defeated by insurgents, according to the U.S. military.

Perhaps that is why Pakistani Prime Minister Yusuf Raza Gilani received such a warm public welcome from President Bush at the White House last week. The president called Pakistan an ally and said that it had made a "strong commitment" to securing the border region. Mr. Gilani asserted his government "is committed to fight" against the outlaws and militants making war against Pakistan.

Pakistani officials have told the United States that they have spotted key border-crossing routes where they will station army units. Not only are Pakistan's tribal areas a safe haven for militants, but also a place from which they mount attacks on U.S. troops in Afghanistan.

Militants killed nine U.S. soldiers July 13 in Afghanistan's Kunar Province, for instance.

Pakistan's initiative may prove to be good news for the United States and its allies in Afghanistan. But U.S. military officials are skeptical, based on past missions that ended unsuccessfully.

One defense official told the Los Angeles Times: "There is a sense of urgency. There is this consensus from the intelligence community that al-Qaida is reconstituting and the primary threat to NATO forces and Afghanistan forces is coming across the border from Pakistan."

Something must be done.