Pakistan's president and British Prime Minister Gordon Brown have pledged to increase counter-terrorism cooperation following the Mumbai terrorist attacks.  Mr. Brown arrived after another tense diplomatic exchange between the region's nuclear-armed rivals, India and Pakistan, after Pakistan's military accused Indian fighter jets of violating Pakistan's airspace in two places.

The alleged violations occurred over places that India says are linked to the militant group accused of plotting the Mumbai attacks.

India denied violations occurred, and Pakistan's president, Asif Zardari, tried to downplay the incident.

"It is a technical incursion, it is not an incursion as such. It is a pattern of two planes when they are flying at 40,000 feet up in the air, when they turn, they slightly enter Pakistani soil," he said.

Tensions between the two rivals have been high since the Mumbai attacks, and politicians have at times pledged cooperation and voiced consternation at their counterparts' investigations.

Pakistani officials have detained dozens of people accused of links to Lashkar e Taiba, the militant group accused of organizing the Mumbai plot. The group was banned by Pakistan in 2002. Over the past week, Pakistani officials also shut down offices of a prominent charity accused of acting as a front for the organization.

India says all 10 of the known attackers were from Pakistan, as well as the planners and financiers of the plot. But President Zardari said India has still not shared any evidence from its investigation in the attack.

He indicated at Sunday's news conference with the British prime minister that he has learned about India's investigation mostly through the news media.

"I am hoping that, once the Indian government completes their investigation and shares the information with us, we will have further leads to further find if there are any culprits on this side of the border, we will take action against them," added Mr. Zardari.

Prime Minister Brown pledged more resources to help in the investigation into the Mumbai terrorist attacks, including new bomb-scanning technology and about $9 million to strengthen Pakistani democratic institutions and fight extremism.

He said the Mumbai attacks and other terrorist plots show that militants in remote areas of Pakistan still threaten people far away in British cities.

"I've told president Zardari that three-quarters of the most serious terrorist plots investigated by the British authorities have links to al-Qaida in Pakistan," said Mr. Brown.

Mr. Brown said he has asked both Indian and Pakistani leaders to allow British authorities to investigate and question suspects in the attacks. He said he specifically asked India's prime minister if British police could question the one captured terrorist from the Mumbai attacks.