Washington, Oct 11 (IANS): The number of US citizens killed amid the ongoing conflict between Israel and Palestine has risen to 14, according to US President Joe Biden, who in a speech has also said Americans were believed to be among those held hostage by Hamas militants.

Speaking from the White House State Dining Room on Tuesday, Biden urged Congress to "take urgent action to fund the national security requirements of our critical partners", saying the funding "is not about party or politics. It's about the security of our world, the security of the United States of America".

Flanked by Vice President Kamala Harris and Secretary of State Antony Blinken, the President said his administration is "surging" additional military assistance to Israel, including ammunitions and interceptors, so as to "make sure Israel does not run out of these critical assets to defend its cities and its citizens", Xinhua news agency reported.

Biden noted that he just spoke on the phone with Israeli Prime Minister Benjamin Netanyahu, the third call between the pair since the drastic escalation of the conflict on Saturday. "I told him, 'If the United States experienced what you're experiencing, our response would be swift decisive and overwhelming,'" Biden said.

Shortly after Biden wrapped up his speech, National Security Advisor Jake Sullivan told reporters during a daily press briefing at the White House that there were "20 or more Americans" who remained unaccounted for in Israel. "We do not know about their condition, and we cannot confirm a precise number of American citizens," he said.

Sullivan declined to weigh in on whether the US would send ground troops to the region to help Israel fight what it had declared to be a war on Hamas. "I'm not going to get into the operational discussions that the president and the prime minister had," he said in reference to the Biden-Netanyahu phone call, adding it's "important for them to be able to keep this discreet channel between them".

The national security advisor said the US is engaged in contingency planning "for any and all escalation scenarios" should they happen, and "we're consulting with allies and partners as well about all of the potential scenarios that might unfold in the days ahead".

The deployment of the USS Gerald R. Ford carrier strike group to the Eastern Mediterranean - which was ordered by Defence Secretary Lloyd Austin on Sunday - was not meant "for Hamas," Sullivan said, but "to send a clear message of deterrence to other states or non-state actors that might seek to widen this war".

In a separate press briefing at the State Department, Matthew Miller, the department's spokesperson, announced that Blinken will soon travel to Israel for talks with "senior leaders in the Israeli government". The secretary will leave the US on Wednesday and arrive in Israel on Thursday.

While in Israel, Blinken is expected "to engage our Israeli partners directly about the situation on the ground" and discuss ways the US can continue to offer its support, Miller said.