But Gilani, responding to questions about Pakistan's efforts to track down Osama bin Laden, said he did not believe the al-Qaeda leader was hiding in his country.
"I doubt the information which you are giving is correct because I don't think Osama bin Laden is in Pakistan," he said.
Brown added that aid being provided by Britain would also go into reconstruction, education and the relocation of people displaced in the fighting.
Last weekend Brown called on Pakistan to step up its action against al-Qaeda and hunt down bin Laden and his deputy Ayman al-Zawahiri, still at large eight years after the September 11, 2001 attacks in the US.
Gilani also called for more clarity on US plans to boost troop levels in Afghanistan, saying he was looking into the implications of the troop surge announced by Barack Obama, the US president, on Tuesday.
"We need more clarity on it, and when we get more clarity on it we can see what we can implement on that plan," he said.
Pakistan has raised fears that an influx of soldiers into Afghanistan could again push fighters over the border, destabilising an already-troubled region.
The US and Britain have urged Pakistan to root out fighters already on its side of the border, in a lawless area from which they frequently attack Nato and Afghan troops.
Obama said in a major speech this week that he was ordering 30,000 more troops into Afghanistan to counter the Taliban. He said a cancer had taken root in Pakistan's border region with its neighbour, and promised US help to end it.