GAZA, Feb 13 (Reuters) - Gaza’s ruling Hamas movement has chosen Yehya Al-Sinwar, freed in a 2011 prisoner swap with Israel after more than 20 years in jail, as its new chief in the Palestinian enclave following an internal election, sources close to the group said on Monday.

Sinwar will be a key decision-maker for Hamas and a member of the executive leadership that draws up policies, including towards Israel. With the group’s overall chief in exile, the Gaza-based officials have wielded more clout in the past decade.

Hani Habeeb, a Gaza political analyst, said Sinwar’s victory sent a message of defiance to Israel and was also likely to complicate efforts further to conclude a stalled reconciliation with rival Palestinian President Mahmoud Abbas’s Fatah faction.

Israel sentenced Sinwar, one of Hamas’s masterminds, to four life terms in the late 1980s. He served 23 years for leading the group’s first security apparatus, which was responsible for tracking and killing Palestinians accused of collaborating with Israel.

Six years ago, Israel freed him in a swap of 1,047 Palestinian prisoners for Israeli soldier Gilad Shalit, who was abducted by Gaza militants in a deadly cross-border raid in 2006.

“Sinwar’s victory confirms that Hamas’s military wing has the upper hand in the movement and his win has made that clearer,” analyst Habib said.

“It is a message to Israel that it should not try to test the capability of the resistance and its decisions. It also sends another message that national reconciliation may become more difficult.”

But Hamza Abu Shanab, an expert in Islamist movements, expected Sinwar to be more open towards Palestinian reconciliation.

“Sinwar’s goal is the liberation of all of Palestine. To achieve this he will be open to dialog with the Arab and Muslim world and will endorse efforts to conclude national unity,” he said.

In 2014, Sinwar backed a Palestinian unity government with Fatah but talks have faltered repeatedly.

Yaron Blum, an analyst and a former employee of Israel’s Shin Bet internal security agency, told Israel Radio that Sinwar would support a harder line against Israel.

“This is a man with a very hawkish approach ... and he will do everything to carry out more attacks and abduct Israeli soldiers and civilians in order to effect more prisoner swaps,” Blum said.

Sinwar is set to replace Ismail Haniyeh in the election that was last held in 2012.

The sources said Sinwar polled best in the vote that was open only to members of Hamas, including those in Israeli jails. Khalil Al-Hayya, a political official, was chosen as Sinwar’s deputy.

Filling the position of Hamas’s political chief, who also speaks for its military wing, will require more time. Haniyeh and Moussa Abu Marzouk, currently the two deputies to the group’s overall leader, Khaled Meshaal, appear to be the leading candidates for the job

(Writing by Nidal Almughrabi; Editing by Ori Lewis and Alison Williams)