The US does not believe Israel has launched a full-scale invasion of Rafah in southern Gaza, White House spokesman John Kirby has said.
He spoke hours after Israeli forces reached the centre of the city and reportedly seized a strategically important hill overlooking the nearby border with Egypt.
US President Joe Biden has previously said a full-scale invasion in Rafah, where hundreds of thousands of civilians are still thought to be sheltering, would cross a red line.
Mr Kirby was also questioned about an Israeli air strike and a resulting fire that killed at least 45 Palestinians at a tented camp for displaced people on Sunday.
Israel has said it believes the fire could have been caused by weapons stored in the vicinity by Hamas exploding.
Mr Kirby told journalists that images from Sunday’s strike, which killed mostly women, children and elderly people, were “heartbreaking” and “horrific”.
“There should be no innocent life lost here as a result of this conflict,” he added.
But he acknowledged that Israel was investigating the incident and said he had “no policy changes to speak to” following the recent events in Rafah.
“We still don’t believe a major ground operation is warranted… and we haven’t seen that at this point,” he said.
Pressed on why the current operation did not meet the definition of a full-scale invasion, Mr Kirby insisted that the president was not “moving the stick”.
“We have not seen them smash into Rafah,” he said.
“We have not seen them go in with large units, large numbers of troops, in columns and formations in some sort of co-ordinated manoeuvre against multiple targets on the ground.”
President Biden said earlier this month that some arms supplies to Israel would be halted in the event of a major ground operation in Rafah.
Israeli Prime Minister Benjamin Netanyahu has described Sunday’s strike as a “tragic mishap”, while vowing to continue the Rafah operation.
The Israeli military has said the strike targeted and killed two senior Hamas officials.
On Tuesday, it said its troops were continuing activities against “terror targets” in Rafah, three weeks after it launched the ground operation there.
Witnesses said Israeli tanks were stationed at al-Awda roundabout, which is considered a key landmark.
Western areas of the city came under intense bombardment overnight on Monday into Tuesday, residents said.
The Israeli military has denied reports on Tuesday that its tank shells hit another tent camp in al-Mawasi, on the coast west of Rafah, which local officials said had killed at least 21 people.
Videos of the incident posted to social media and analysed by BBC Verify showed multiple people with serious injuries.
There was no clear sign of a blast zone or crater, making it impossible to ascertain the cause of the incident. The location – verified through reference to surrounding buildings – is between Rafah and al-Mawasi, and lies south of the Israeli military’s designated humanitarian zone.
Israel has insisted that victory in its seven-month war with Hamas in Gaza is impossible without taking Rafah and rejected warnings that it could have catastrophic humanitarian consequences.
The UN says around a million people have now fled the fighting in Rafah, but several hundred thousand more could still be sheltering there.
The Israel Defense Forces began what they called “targeted” ground operations against Hamas fighters and infrastructure in the east of Rafah on 6 May.
Since then, tanks and troops have gradually pushed into built-up eastern and central areas while also moving northwards along the 13km (8-mile) border with Egypt.
Israel launched a military campaign in Gaza to destroy Hamas in response to the group’s cross-border attack on southern Israel on 7 October, during which about 1,200 people were killed and 252 others were taken hostage.
At least 36,090 people have been killed in Gaza since then, according to the Hamas-run health ministry.