ISLAMABAD, Pakistan — The Supreme Court on Monday suspended the interior minister after he failed to provide proof that he had surrendered his British passport. The order was part of a wider court investigation into lawmakers who hold dual nationality with Western countries, including the United States.

The three-judge bench, headed by Chief Justice Iftikhar Muhammad Chaudhry, suspended the minister, Rehman Malik, from the Senate, automatically removing him from his position as interior minister.

Mr. Malik, who is one of President Asif Ali Zardari’s closest aides, said that he surrendered his British nationality before he was elected to the Senate in 2008, but that he could not provide the necessary documentation on Monday.

The government, which has fought several legal battles in the Supreme Court this year, did not immediately respond. But there was media speculation that it would quickly appoint Mr. Malik as an “adviser” to the prime minister, with full ministerial powers — effectively retaining him in his present post.