Islamabad, Jul 31 (IANS): The US has said its relationship with Pakistan was "essential" in the fight against terror. The ties were, however, "complicated and difficult" at times.

"Without addressing specific methods, I would say simply that we believe our relationship with Pakistan is essential to fighting terrorism and terrorists, fighting Al Qaeda," Associated Press of Pakistan (APP) quoted US President Barack Obama's spokesman Jay Carney as saying in Washington.

Carney was asked by reporters about a call by former US intelligence chief Admiral (retd) Dennis Blair for an immediate halt to drone attacks on Pakistani soil.

"We also make no apologies for the need to go after terrorists, members of Al Qaeda, wherever they are. And that is certainly true about the mission to eliminate Osama bin Laden," Carney said.

Osama was killed in a US special forces mission in Pakistan's Abbottabad city in May. The US did not inform Pakistan about the operation, saying it may have been sabotaged.

Blair recently said Washington's unilateral actions were harming ties with Islamabad and that Pakistan should be given control over drone strikes.

According to APP, the White House official's remarks indicated that the US understands that tensions were arising from its unilateral anti-militant actions. But that Washington wants to maintain close ties with Islamabad and fight terrorists simultaneously.

"And I think that I understand that that creates tension. And we have... we engage with the Pakistanis to discuss these issues all the time. But the relationship is important and, obviously, fighting terrorism is important," the spokesman said.