Benghazi, Libya (CNN) -- Four rockets struck the compound belonging to Libyan leader Moammar Gadhafi Thursday, a Libyan government official told CNN.

After the blasts, which could be heard in the center of Tripoli, sirens blared and at least two emergency vehicles could be seen speeding toward the Bab al-Aziziya compound. It was not immediately clear whether anyone was hurt.

On May 1, the Libyan government said another attack on the same compound had killed Gadhafi's son Saif al-Arab Gadhafi and three of the leader's grandchildren.

Thursday's strike came a day after spokesmen for the Libyan rebels sparred with a spokesman for the Libyan government over who was in control of the airport in the besieged city of Misrata.

During the day, Shamsiddin Abdulmolah of the Transitional National Council said the airport, located in the southern part of the war-torn city, had fallen to "revolutionaries" after opposition fighters in nearby Zlaitin were able to join their counterparts in Misrata.

During the night, government spokesman Musa Ibrahim said government forces were in control of the airport and the seaport in Misrata. He said rebel forces had been there "for (a) short time, and left."

But a rebel spokesman in Misrata, who has asked to be identified solely as Mohamed, said late Wednesday night that the rebels had retained control of the airport and were also in control of a civil defense base beyond the airport.

The capture of the airport would be key for rebels fighting the forces of Libyan leader Moammar Gadhafi since it would provide an important entry point for humanitarian aid.

Two months of fighting and the ongoing shelling of the Misrata port have prevented most aid ships from docking there, leaving the city "at the forefront" of U.N. humanitarian concerns, a top U.N. official told the Security Council this week.

NATO warplanes and missiles have been pounding Gadhafi's forces since March as Gadhafi's troops try to quash a nearly 3-month-old revolt against his nearly 42 years of rule.

In Misrata, Abdulmolah said an unknown number of casualties occurred in the fighting. He also reported that the oil-rich town of Jakharra, in the interior of the country, fell Tuesday night to opposition forces and that Gadhafi's forces were surrounded in the oasis towns of Awjila and Jalu.

The NATO mission is intended to enforce a U.N. Security Council resolution that calls for the protection of civilians. U.S. President Barack Obama and NATO Secretary-General Anders Fogh Rasmussen will meet at the White House on Friday to discuss the alliance's role, the White House said Wednesday.

NATO said Wednesday that vehicle and ammunition storage facilities, a surface-to-air missile launcher and an anti-aircraft gun had been hit in the Tripoli area. It also said in a news release that ambulance storage facilities were struck in Mizdah and Qaryat.

As for Misrata, Marie Colvin, the Middle East correspondent for Britain's Sunday Times, told CNN that rebel forces defending the city from government troops were making "meter-by-meter" gains despite heavy shelling and rocket attacks.

Units loyal to Gadhafi have been firing rockets and artillery shells into residential neighborhoods, leaving a nearby emergency room full of women, children and old men, she said.

"The rebels are very much trying, at a minimum, to push back Gadhafi's lines so he simply can't do that," Colvin said Tuesday.

As for aid, a ship carrying supplies from the International Committee of the Red Cross docked Tuesday in Misrata, but the ongoing fighting had deterred captains of other ships from trying to enter the port, Colvin said.

The ICRC said the vessel was carrying medical supplies, spare parts to repair water and electrical supply systems and 8,000 jars of baby food.

On the front lines of the battle, bullets were whizzing past "like very angry hornets," Colvin said. At least 70 rebels have been wounded -- but they have held their line, "and meter by meter were able to advance," she said.

"They're defending their homes. They're defending their families, and they are not giving up an inch. They are fighting," Colvin said.

The first shipment of nonlethal aid from the United States to the Libyan opposition arrived Tuesday in Benghazi, U.S. State Department spokesman Mark Toner said.

It included more than 10,000 meals that are permissible under Islamic law. Other items en route from the U.S. Defense Department include medical supplies, tents, uniforms, boots and protective gear.

Almost 750,000 people have fled the country amid the fighting, and another 58,000 are displaced within Libya, Valerie Amos, the U.N. undersecretary-general for humanitarian affairs, told the Security Council Monday.

Another 5,000 are stranded at border crossings between Libya, Tunisia and Niger, Amos said. Others have tried to flee by sea, but one such attempt appears to have ended in disaster for hundreds of refugees as their ship capsized off the capital, Tripoli.

CNN's Nima Elbagir contributed to this story.