India's accusation of Pakistan's involvement in the July 11 Mumbai train blasts was 'regrettable,' President Pervez Musharraf [Images] has said.

"Pakistan is fighting a war against terrorism on principles. India blaming Pakistan for Mumbai bomb blasts is regrettable," Musharraf said during a meeting with Prime Minister Shaukat Aziz.

Musharraf, who discussed with Aziz the deliberations he had with Prime Minister Manmohan Singh [Images] in Cuba, said, "The joint declaration issued in Havana might take forward the movement for resolution of all conflicts including the core issue of Kashmir."

Musharraf said he had held a productive meeting with the Indian prime minister and they agreed to formulate a strategy to combat terrorism, according to Pakistani daily The News.

Terming his US visit as 'very fruitful,' the General said it will strengthen bilateral ties.

"All the objectives of the visit stood achieved. The strategic relations between Pakistan and the US would be consolidated," he said.

Musharraf said he had presented Pakistan's stance forcefully on Waziristan peace deal and he succeeded in convincing the western countries that the accord was meant to end Talibanization, establish peace and develop the tribal areas.