Libyan leader Moammar Gadhafi has vowed to fight to the end, as NATO warplanes pounded Tripoli with some of the most intense airstrikes since the coalition began its campaign in March.

Mr. Gadhafi made his vow in a fiery audio speech broadcast Tuesday on state television. He said the Libyan people will not surrender and will stay in their country until the end.

The Libyan leader was last seen in a brief appearance on state television late last month.

On Tuesday, the NATO airstrikes caused a long series of explosions that rocked the Libyan capital. Witnesses said they saw smoke in the area of Mr. Gadhafi's sprawling compound in the city.

A Libyan government spokesman said around 30 people were killed in 60 airstrikes on Tripoli. His account could not be independently confirmed.

Meanwhile, world powers are increasing pressure on Mr. Gadhafi's government. The European Union said Tuesday it plans to add six Libyan ports under the government's control to its sanctions list.

Also, Russian envoy Mikhail Margelov met with members of the opposition Transitional National Council in the rebel stronghold, Benghazi. He said Moscow is interested in Libya being a sovereign and democratic country that is a “worthy member of the international community.”

China's Foreign Ministry said one of its diplomats based in Egypt recently held talks with the Libyan rebel council. Libya's foreign minister is on a three-day visit to Beijing.

China and Russia both abstained when the U.N. Security Council voted in March to establish a no-fly zone over Libya, and they have called for a negotiated solution to the conflict.

In Brussels, NATO Secretary-General Anders Fogh Rasmussen said he would use a defense ministers' meeting Wednesday to repeat calls for the alliance to step up involvement in the Libya operation.