Israel ramped up its airstrikes Monday in Gaza, where the death toll is rising rapidly, and the United States advised Israel to delay an expected ground invasion to allow more time to negotiate the release of hostages taken by Hamas militants.

Israel has allowed two small aid convoys but no fuel to enter the besieged coastal enclave, where there has been a power blackout for nearly two weeks. Hospitals say they are scrounging for generator fuel in order to keep operating life-saving medical equipment and incubators for premature babies.

For months after Ukraine's Western allies limited sales of Russian oil to $60 per barrel, the price cap was still largely symbolic. Most of Moscow's crude — its main moneymaker — cost less than that.

But the cap was there in case oil prices rose — and would keep the Kremlin from pocketing extra profits to fund its war in Ukraine. That time has now come, putting the price cap to its most serious test so far and underlining its weaknesses.

A premature baby squirms inside a glass incubator in the neonatal ward of al-Aqsa Hospital in the central Gaza Strip. He cries out as intravenous lines are connected to his tiny body. A ventilator helps him breathe as a catheter delivers medication and monitors flash his fragile vital signs.

His life hinges on the constant flow of electricity, which is in danger of running out imminently unless the hospital can get more fuel for its generators. Once the generators stop, hospital director Iyad Abu Zahar fears that the babies in the ward, unable to breathe on their own, will perish.

Israeli warplanes are striking Gaza ahead of an expected ground offensive in the besieged territory. Fears of a widening war have grown as Israel struck targets in the occupied West Bank, Syria and Lebanon and traded fire with Lebanon's Hezbollah militant group.

Two aid convoys arrived in the Gaza Strip over the weekend through the Rafah crossing from Egypt. Israel said the trucks carried food, water and medical supplies. Israel has not allowed in fuel, which is critically needed for water and sanitation systems and hospitals.

Hezbollah announced the deaths of seven more militants as clashes along the Lebanon-Israel border intensified and the Israeli prime minister warned Lebanon on Sunday not to let itself get dragged into a new war.

Israeli soldiers and Hezbollah militants have traded fire across the border since Israel's war with the Palestinian group Hamas began, but the launches so far have targeted limited areas.

Hezbollah deputy chief Sheikh Naim Qassem has vowed that Israel will pay a high price whenever it starts a ground offensive in the Gaza Strip, saying that his Lebanon-based group already is "in the heart of the battle."

The comments by Qassem came as Israel shelled and made drone strikes in southern Lebanon and Hezbollah fired rockets and missiles toward Israel. Hezbollah said six of its fighters were killed Saturday, the highest daily toll since the violence began two weeks ago.

By Asher Kaufman, University of Notre Dame

Lebanon, which is teetering on the edge of economic and political collapse, risks becoming entangled in the escalating war between Israel and Hamas.

U.S. Defense Secretary Lloyd Austin announced late Saturday he was sending additional air defense systems to the Middle East as well as putting more troops on prepare-to-deploy orders.

Austin said the U.S. would be delivering a Terminal High Altitude Area Defense, or THAAD, battery along with additional Patriot missile defense system batteries “to locations throughout the region to increase force protection for U.S. troops.” Bases in Iraq and Syria have been repeatedly targeted by drones in the days since hundreds were killed in a hospital blast in Gaza, and the destroyer USS Carney intercepted land attack cruise missiles in the Red Sea shot from Yemen on Thursday.

Israeli warplanes struck targets across Gaza overnight and into Sunday, as well as two airports in Syria and a mosque in the occupied West Bank allegedly used by militants, as the two-week-old war with Hamas threatened to spiral into a broader conflict.

Israel has traded fire with Lebanon's Hezbollah on a near-daily basis since the war began, and tensions are soaring in the Israeli-occupied West Bank, where Israeli forces have battled militants in refugee camps and carried out two airstrikes in recent days.

Police in Cyprus said Saturday they arrested four Syrians on suspicion of setting off a small explosive device that caused no damage not far from Israeli Embassy in the capital Nicosia.

Police said the four, ranging in ages between 17 and 21, face charges of attempted destruction of property using explosives, possession and use of explosives and possession of a knife.