ISTANBUL — The Turkish charity that led the flotilla involved in a deadly Israeli raid has extensive connections with Turkey’s political elite, and the group’s efforts to challenge Israel’s blockade of Gaza received support at the top levels of the governing party, Turkish diplomats and government officials said.

The charity, the Humanitarian Relief Foundation, often called I.H.H., has come under attack in Israel and the West for offering financial support to groups accused of terrorism. But in Turkey the group has helped Prime Minister Recep Tayyip Erdogan shore up support from conservative Muslims ahead of critical elections next year and improve Turkey’s standing and influence in the Arab world.

According to a senior Turkish official close to the government, who spoke on the condition of anonymity because of the political delicacy of the issue, as many as 10 Parliament members from Mr. Erdogan’s governing Justice and Development Party were considering boarding the Mavi Marmara, the ship where the deadly raid occurred, but were warned off at the last minute by senior Foreign Ministry officials concerned that their presence might escalate tensions too much.

When leaders of the charity returned home after nine Turks died in the Israeli raid, they were warmly embraced by top Turkish officials, said Huseyin Oruc, deputy director of the charity, who was aboard the flotilla.