Pakistani Prime Minister Yusuf Raza Gilani telephoned Afghan President Hamid Karzai Wednesday to express “serious concern” regarding the activities of militants along the countries' common border.

In a statement, the prime minister's office said Mr. Gilani told President Karzai the Pakistani army was exercising “utmost restraint,” despite repeated cross-border incursions by Afghan militants into Pakistan. Mr. Gilani said the issue needs to be defused quickly. He said Islamabad has requested that NATO immediately convene a meeting to discuss border coordination among regional commanders.

Prime Minister Gilani also urged Mr. Karzai to ask NATO and Afghan military commanders to join Pakistan's efforts to defuse the situation and avoid any further loss of innocent life on both sides.

According to the statement, President Karzai expressed his readiness to send coalition and Afghan commanders to the meeting, adding the two countries can thwart the militants through close coordination and understanding.

The telephone call took place hours after Pakistani officials said hundreds of militants crossed from Afghanistan and attacked several border villages in the Upper Dir region of northwestern Pakistan, clashing with soldiers and local militias.

There were reports of casualties among both militants and local tribesmen, but the exact number is unclear. The region is largely closed to reporters and outsiders due to security and government restrictions.

Pakistan says militants allegedly coming from Afghan bases have killed more than 55 soldiers during the past month, while Afghanistan accuses Pakistan of intentionally firing hundreds of rockets into its territory, killing at least 36 civilians. Pakistan's military denies the allegation but says several rounds fired at militants may have landed over the border.

In other violence, Pakistani intelligence officials said troops backed by helicopters killed at least four militants in Miranshah, the main town in the North Waziristan tribal region, after the militants attacked them.

The Pakistani military has launched a ground offensive against the Pakistani Taliban in the tribal belt but refuses to expand its operations to North Waziristan. Military officials say they want to secure gains made in other tribal regions before tackling another area.