Afghanistan's President Hamid Karzai (L) and Pakistan's President Asif Ali Zardari (C) look as Iranian counterpart Mahmoud Ahmadinejad (R) speaks during a joint press conference at the Presidential Palace in Islamabad on Friday. – Photo by AFP

ISLAMABAD: President Asif Ali Zardari on Friday vowed to continue with a proposed pipeline project with Iran despite American warnings of sanctions, saying Islamabad's relations with Tehran would not ''be undermined by international pressure of any kind.''

Asif Ali Zardari made the comments alongside Iranian President Mahmoud Ahmadinejad, who is facing fresh Western pressure over his country's nuclear program.

Pakistan faces chronic energy shortages that feed anti-government anger, hobble industry and trigger unrest in an already poor country. The proposed pipeline would deliver natural gas from Iran to Pakistan, and go some ways to improving the situation.

But the US wants Pakistan to halt the project because it would undercut international pressure to isolate Iran over its nuclear program. The issue is an irritant, though by no means the largest, in already badly strained relationship between Islamabad and Washington.

Iran maintains its nuclear program is entirely peaceful, but the US and its allies worry the program is designed to ultimately deliver a nuclear weapon.

Zardari was asked about the opposition to the pipeline project. ''Pakistan is lobbying the world, and our point of view is being accepted,'' he said. ''Our bilateral relationships cannot be undermined by any international pressure of any kind.''

The pipeline project was first proposed in the 1990s, but has been plagued by delays.

Pakistan and Iran finalised the gas deal last year. Under the contract, Iran will export 760 million cubic feet (21.5 million cubic meters) of gas per day to Pakistan through a new pipeline beginning in 2014. The construction of the pipeline is estimated to cost some $7 billion.

Ahmadinejad didn't reference the nuclear program, but took a swipe at Washington, accusing it of being the cause of the problems in Afghanistan. The two-day conference, also attended by Afghan President Hamid Karzai, focused on Taliban peace talks and other regional issues.