Israeli Prime Minister Benjamin Netanyahu has said he was considering military aid to Ukraine and was willing to serve as a mediator, following US calls for more active involvement.

Netanyahu made no firm commitments to Ukraine and Israel has preserved a relationship with Russia, which controls the skies in neighbouring Syria and has turned a blind eye to Israeli strikes on targets of Iran.

Netanyahu was asked in an interview with CNN if Israel could provide assistance to Ukraine such as Iron Dome, the US-backed technology that defends Israel from air attack .

"Well, I'm certainly looking into it," Netanyahu said.

He confirmed that the United States has shifted a little-known stockpile of artillery it stations in Israel to Ukraine and he cast the Israeli state's own operations against Iran as part of a similar effort.

The United States is readying more than $2 billion worth of military aid for Ukraine that is expected to include longer-range rockets for the first time and other munitions and weapons, two US officials briefed on the matter have told the Reuters news agency.

The weapons aid is expected to be announced as soon as later this week, the officials said. It is also expected to include support equipment for Patriot air defence systems, precision guided munitions and Javelin anti-tank weapons, they added.

One of the officials said that a portion of the package, $1.725 billion, would come from a fund known as the Ukraine Security Assistance Initiative, which allows President Joe Biden's administration to get weapons from industry rather than from existing US weapons stocks.

The funds would go toward the purchase of a new weapon, Ground Launched Small Diameter Bomb (GLSDB), which have a range of 150 km. The United States has rebuffed requests for the 297-km range ATACMS missile.

The longer range of the GLSDB glide bomb could allow Ukraine to hit valuable military targets that have been out of reach and help it continue pressing its counterattacks by disrupting Russia further behind its lines.