The Obama administration said Friday it will resume some military sales to Bahrain, while continuing to withhold certain types of defense equipment because of human rights concerns in the Persian Gulf kingdom.

A State Department announcement recognized “a number of serious unresolved human rights issues” and cited increased “polarization” in Bahrain, where arrests and repression against increasingly violent political protests have increased despite the government’s pledges to begin a political dialogue with its opponents.

The decision to lift the restrictions, which had frozen tens of millions of dollars worth of planned arms sales last fall, was based on “our desire to help the Bahrainis maintain their external defense capabilities, and a determination that it is in U.S. national interest to let these things go forward,” said one of several senior administration officials who briefed reporters on the condition of anonymity.

Bahrain, the home of the U.S. Fifth Fleet, lies off the coast of Saudi Arabia, opposite Iran.

The equipment released for sale did not include requested items such as TOW missiles or Humvees or supplies such as tear gas, stun grenades and other items that could be “used against protesters in any scenario,” one official said.

The officials declined to provide a complete list of items approved for sale but said they included coastal patrol boats and a frigate that have been designated as excess U.S. military material, as well as engine upgrades for Bahrain’s fleet of F-16 fighter jets. Other sources said the list also included upgrades for Bahrain’s air defense communications, ground-based radar, air-to-air and ground-to-air missile systems and Cobra helicopters, as well as defense radar components and night-vision equipment.

Congressional approval would be required for transfer of some of the newly released defense items, assuming Bahrain decides to purchase them. Administration officials briefed congressional staffs Friday morning on the decision, which some lawmakers criticized as amounting to rewarding Bahrain for its human rights failings.

“This is exactly the wrong time to be selling arms to the government of Bahrain,” said Sen. Ron Wyden (D-Ore.). “Things are getting worse, not better. . . . Reform is the ultimate goal and we should be using every tool and every bit of leverage we have to achieve that goal.”

Tom Malinowski, Washington director for Human Rights Watch, gave the administration “credit for pushing very hard” for the Bahraini government to implement its commitments to open the political process. “I don’t think there’s any question about what [the administration] is trying to achieve in Bahrain or the sense of urgency they feel.”

But Malinowski characterized the decision to resume some arms sales as shortsighted, saying that “the number one U.S. security interest in Bahrain right now is not making sure they have slightly better F-16 engines, it’s making sure that they implement the reforms needed to make the relationship sustainable over the long term.”

Administration officials declined to explain the timing of the decision, but it coincided with a visit to Washington this week by Bahrain Crown Prince Salman bin Hamad al-Khalifa, who met with Vice President Biden, Secretary of State Hillary Rodham Clinton and Defense Secretary Leon E. Panetta. Officials said U.S. leaders raised a number of human rights concerns in the meetings, including the detention of opposition figures — some this week — for nonviolent public protests.

Within the Bahraini ruling family, the prince is considered a moderate who favors political dialogue. Congressional and human rights sources speculated that the administration hoped to bolster his standing with King Hamad bin Isa al-Khalifa.

The administration has been criticized for its relatively muted approach to political oppression in Bahrain, compared with its support of political uprisings elsewhere since the Arab Spring demonstrations began early last year.

After large demonstrations by majority Shiites against Bahrain’s ruling Sunni monarchy last year, Saudi Arabia and other Persian Gulf countries, responding to a Bahraini government request, sent troops to help quell the protests. Opposition to the monarchy has become increasingly violent in response to continuing arrests and police crackdowns.

Although the king was widely praised last fall for accepting the recommendations of an independent commission that investigated the Saudi-supported crackdown, he has failed to implement promised reforms and arrests have continued.

The escalating violence and repression has presented the Obama administration with a complex panorama of conflicting priorities. Its genuine concern about political reforms in Bahrain is set against the backdrop of a long-standing security relationship with Bahrain and an escalating threat from Iran.

In late March, Clinton met with the six members of the Gulf Cooperation Council — Bahrain, Saudi Arabia, Kuwait, Oman, Qatar and the United Arab Emirates — to reach a new security cooperation agreement. The accord called for a regional missile defense system and improved security coordination among the six countries and the United States.