The Gadhafi government carried out a lobbying operation to try to stop NATO's bombardment of Libya, Britain's The Guardian newspaper reported Friday, citing secret documents.

The newspaper said the documents in Tripoli showed Libya's rulers believed NATO forces were likely to launch a full-scale invasion in either late September or October.

It said the documents also showed that Tripoli approached American officials all the way up to President Barack Obama.

Since NATO took command of air strikes on Libya on March 31, its aircraft have conducted more than 20,000 sorties including 7,635 strike sorties, the alliance said Thursday.

Sixteen ships under NATO command are also patrolling the central Mediterranean to enforce a U.N. arms embargo.

The paper also said the documents showed the Libyan prime minister wrote a letter to Obama in June, in which he addressed him as Mr. President, and politely complained about Washington's unprecedented decision to confiscate Libya's assets.

It also said Rep. Dennis Kucinich, D-Ohio, a dissenter from Obama's foreign policy who voted against the NATO mission, declined a Libyan regime overture to visit as part of a peace mission. The plan was for Kucinich to meet senior Libyan officials, including Gaddafi.

Because of the efforts I had made early on to bring an end to the war, I started to get calls from Libya, including from the prime minister, the Guardian quoted Kucinich as saying.

I had several requests to go to Libya. I made it clear I could not negotiate on behalf of the administration. I said I was speaking as a member of Congress involved in the issue and willing to listen to what they had to say. But given that Libya was under attack, it did not seem a promising place to hold meetings.

(Reporting by Stephen Mangan; Editing by Alison Williams)