Protesters with hands covered in red paint repeatedly interrupted a congressional hearing on US military aid, demanding Washington stop funding Israel's war on Gaza.

Secretary of State Antony Blinken and Defense Secretary Lloyd Austin on Tuesday were appealing to the Senate Appropriations Committee for billions of dollars in military assistance to support Israel, Ukraine and other security costs.

Some two dozen spectators raised hands covered in paint in a symbol of the bloodshed in Gaza since Israel began its bombardment of the Palestinian territory after Hamas' attack earlier this month.

Several wore messages of "Free Gaza" written on their arms and held signs demanding "No more $$$ 4 Israel," while some cried out "Ceasefire now," "Palestinians are not animals" and "Shame on you all."

One man wore a shirt reading "Stop backing genocide."

Blinken interrupted

Blinken was forced to stop speaking several times as some demonstrators were escorted out by police.

President Joe Biden has asked Congress for more than $105 billion in security spending, including $14.3 billion for its staunch ally Israel.

Israeli troops and Hamas fighters were engaged in "fierce battles" in Gaza on Tuesday, Israel's military said, as tanks and armoured bulldozers advanced through the ruins of the embattled territory, which the United Nations said is facing "unprecedented" humanitarian needs.

Israel's response to the Hamas attack has now killed more than 8,500 people, according to the latest count given by the Health Ministry in Gaza, many of them children.