Washington - Lithuania is among the alternate countries that could host a US missile-defence site if negotiations with Poland falter, the Pentagon said Tuesday, expressing an urgency to reach an agreement before President George W Bush leaves office.

"We are hopeful that we can soon reach a deal with the Poles, but we have always said that there are other options available to us," Pentagon spokesman Geoff Morrell said. "There are several other European nations that could host the interceptors, and Lithuania is one of them."

With Bush due to leave office in January, Morrell said concerns that the next administration won't support the missile defence plans were "absolutely" a factor in how the United States proceeds in the negotiations with Warsaw.

"I don't want to put a timetable on it, but clearly time is of the essence. We want to get a deal done," Morrell said, pointing to the need to address Iran's growing ballistic missile capability.

"That is also why we do not close the door on perhaps having to pursue a backup option," he said.

The United States is to sign a deal next month with the Czech Republic for the hosting of a missile-defence radar site but has still not concluded an agreement with Poland, which would base 10 interceptor missiles.

Warsaw wants the United States to upgrade Polish air-defence capabilities over concerns that Poland would be at greater risk by agreeing to host the 10 interceptor missiles. Morrell said that the United States remains focused on completing a deal with Poland and has not begun negotiations with alternate countries.

The United States continues to negotiate a package to assist the Poles with improving air defences, Morrell said, adding that the Poles are asking Washington to "significantly" modernize their air defenses.

"We're in the midst of a conversation and negotiation on trying to determine what is needed and what we can afford to do and to get a deal done with the Poles," he said.

Bush wants to deploy a system to Eastern Europe to defend against an Iranian missile, a decision that has angered Russia, which believes the system poses a threat to its nuclear missile arsenal.

The United States contends that the defence system is much too small to fend off hundreds of Russian missiles, but the dispute remains unresolved and has largely contributed to the lowest point in relations between the two countries since the end of the Cold War. Czech and Polish voters have also been sceptical about the plans. (dpa)